diff --git a/src/share/classes/java/util/AbstractMap.java b/src/share/classes/java/util/AbstractMap.java
index fdca2aa79931f50363fdf413b8a547ffe4fecbd2..7c5153fc3bb98d64b274e23208a3adf1f727aef2 100644
--- a/src/share/classes/java/util/AbstractMap.java
+++ b/src/share/classes/java/util/AbstractMap.java
@@ -543,6 +543,8 @@ public abstract class AbstractMap<K,V> implements Map<K,V> {
     /**
      * Utility method for SimpleEntry and SimpleImmutableEntry.
      * Test for equality, checking for nulls.
+     *
+     * NB: Do not replace with Object.equals until JDK-8015417 is resolved.
      */
     private static boolean eq(Object o1, Object o2) {
         return o1 == null ? o2 == null : o1.equals(o2);
diff --git a/src/share/classes/java/util/Collections.java b/src/share/classes/java/util/Collections.java
index 56f16f6809bfacfff63045db32b9d428b939f2f1..bbb987ec58fb93be6e8a8a48019b059ce5965d49 100644
--- a/src/share/classes/java/util/Collections.java
+++ b/src/share/classes/java/util/Collections.java
@@ -27,6 +27,7 @@ package java.util;
 import java.io.Serializable;
 import java.io.ObjectOutputStream;
 import java.io.IOException;
+import java.io.InvalidObjectException;
 import java.lang.reflect.Array;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
@@ -138,7 +139,7 @@ public class Collections {
      *
      * <p>The implementation was adapted from Tim Peters's list sort for Python
      * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
-     * TimSort</a>).  It uses techiques from Peter McIlroy's "Optimistic
+     * TimSort</a>).  It uses techniques from Peter McIlroy's "Optimistic
      * Sorting and Information Theoretic Complexity", in Proceedings of the
      * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
      * January 1993.
@@ -199,7 +200,7 @@ public class Collections {
      *
      * <p>The implementation was adapted from Tim Peters's list sort for Python
      * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
-     * TimSort</a>).  It uses techiques from Peter McIlroy's "Optimistic
+     * TimSort</a>).  It uses techniques from Peter McIlroy's "Optimistic
      * Sorting and Information Theoretic Complexity", in Proceedings of the
      * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
      * January 1993.
@@ -1213,6 +1214,94 @@ public class Collections {
         public E last()                    {return ss.last();}
     }
 
+    /**
+     * Returns an unmodifiable view of the specified navigable set.  This method
+     * allows modules to provide users with "read-only" access to internal
+     * navigable sets.  Query operations on the returned navigable set "read
+     * through" to the specified navigable set.  Attempts to modify the returned
+     * navigable set, whether direct, via its iterator, or via its
+     * {@code subSet}, {@code headSet}, or {@code tailSet} views, result in
+     * an {@code UnsupportedOperationException}.<p>
+     *
+     * The returned navigable set will be serializable if the specified
+     * navigable set is serializable.
+     *
+     * @param s the navigable set for which an unmodifiable view is to be
+     *        returned
+     * @return an unmodifiable view of the specified navigable set
+     * @since 1.8
+     */
+    public static <T> NavigableSet<T> unmodifiableNavigableSet(NavigableSet<T> s) {
+        return new UnmodifiableNavigableSet<>(s);
+    }
+
+    /**
+     * Wraps a navigable set and disables all of the mutative operations.
+     *
+     * @param <E> type of elements
+     * @serial include
+     */
+    static class UnmodifiableNavigableSet<E>
+                             extends UnmodifiableSortedSet<E>
+                             implements NavigableSet<E>, Serializable {
+
+        private static final long serialVersionUID = -6027448201786391929L;
+
+        /**
+         * A singleton empty unmodifiable navigable set used for
+         * {@link #emptyNavigableSet()}.
+         *
+         * @param <E> type of elements, if there were any, and bounds
+         */
+        private static class EmptyNavigableSet<E> extends UnmodifiableNavigableSet<E>
+            implements Serializable {
+            private static final long serialVersionUID = -6291252904449939134L;
+
+            public EmptyNavigableSet() {
+                super(new TreeSet<E>());
+            }
+
+            private Object readResolve()        { return EMPTY_NAVIGABLE_SET; }
+        }
+
+        @SuppressWarnings("rawtypes")
+        private static final NavigableSet<?> EMPTY_NAVIGABLE_SET =
+                new EmptyNavigableSet<>();
+
+        /**
+         * The instance we are protecting.
+         */
+        private final NavigableSet<E> ns;
+
+        UnmodifiableNavigableSet(NavigableSet<E> s)         {super(s); ns = s;}
+
+        public E lower(E e)                             { return ns.lower(e); }
+        public E floor(E e)                             { return ns.floor(e); }
+        public E ceiling(E e)                         { return ns.ceiling(e); }
+        public E higher(E e)                           { return ns.higher(e); }
+        public E pollFirst()     { throw new UnsupportedOperationException(); }
+        public E pollLast()      { throw new UnsupportedOperationException(); }
+        public NavigableSet<E> descendingSet()
+                 { return new UnmodifiableNavigableSet<>(ns.descendingSet()); }
+        public Iterator<E> descendingIterator()
+                                         { return descendingSet().iterator(); }
+
+        public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
+            return new UnmodifiableNavigableSet<>(
+                ns.subSet(fromElement, fromInclusive, toElement, toInclusive));
+        }
+
+        public NavigableSet<E> headSet(E toElement, boolean inclusive) {
+            return new UnmodifiableNavigableSet<>(
+                ns.headSet(toElement, inclusive));
+        }
+
+        public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
+            return new UnmodifiableNavigableSet<>(
+                ns.tailSet(fromElement, inclusive));
+        }
+    }
+
     /**
      * Returns an unmodifiable view of the specified list.  This method allows
      * modules to provide users with "read-only" access to internal
@@ -1240,6 +1329,7 @@ public class Collections {
     static class UnmodifiableList<E> extends UnmodifiableCollection<E>
                                   implements List<E> {
         private static final long serialVersionUID = -283967356065247728L;
+
         final List<? extends E> list;
 
         UnmodifiableList(List<? extends E> list) {
@@ -1682,7 +1772,8 @@ public class Collections {
             private static class UnmodifiableEntry<K,V> implements Map.Entry<K,V> {
                 private Map.Entry<? extends K, ? extends V> e;
 
-                UnmodifiableEntry(Map.Entry<? extends K, ? extends V> e) {this.e = e;}
+                UnmodifiableEntry(Map.Entry<? extends K, ? extends V> e)
+                        {this.e = Objects.requireNonNull(e);}
 
                 public K getKey()        {return e.getKey();}
                 public V getValue()      {return e.getValue();}
@@ -1734,24 +1825,151 @@ public class Collections {
 
         private final SortedMap<K, ? extends V> sm;
 
-        UnmodifiableSortedMap(SortedMap<K, ? extends V> m) {super(m); sm = m;}
+        UnmodifiableSortedMap(SortedMap<K, ? extends V> m) {super(m); sm = m; }
+        public Comparator<? super K> comparator()   { return sm.comparator(); }
+        public SortedMap<K,V> subMap(K fromKey, K toKey)
+             { return new UnmodifiableSortedMap<>(sm.subMap(fromKey, toKey)); }
+        public SortedMap<K,V> headMap(K toKey)
+                     { return new UnmodifiableSortedMap<>(sm.headMap(toKey)); }
+        public SortedMap<K,V> tailMap(K fromKey)
+                   { return new UnmodifiableSortedMap<>(sm.tailMap(fromKey)); }
+        public K firstKey()                           { return sm.firstKey(); }
+        public K lastKey()                             { return sm.lastKey(); }
+    }
 
-        public Comparator<? super K> comparator() {return sm.comparator();}
+    /**
+     * Returns an unmodifiable view of the specified navigable map.  This method
+     * allows modules to provide users with "read-only" access to internal
+     * navigable maps.  Query operations on the returned navigable map "read
+     * through" to the specified navigable map.  Attempts to modify the returned
+     * navigable map, whether direct, via its collection views, or via its
+     * {@code subMap}, {@code headMap}, or {@code tailMap} views, result in
+     * an {@code UnsupportedOperationException}.<p>
+     *
+     * The returned navigable map will be serializable if the specified
+     * navigable map is serializable.
+     *
+     * @param m the navigable map for which an unmodifiable view is to be
+     *        returned
+     * @return an unmodifiable view of the specified navigable map
+     * @since 1.8
+     */
+    public static <K,V> NavigableMap<K,V> unmodifiableNavigableMap(NavigableMap<K, ? extends V> m) {
+        return new UnmodifiableNavigableMap<>(m);
+    }
 
-        public SortedMap<K,V> subMap(K fromKey, K toKey) {
-            return new UnmodifiableSortedMap<>(sm.subMap(fromKey, toKey));
+    /**
+     * @serial include
+     */
+    static class UnmodifiableNavigableMap<K,V>
+          extends UnmodifiableSortedMap<K,V>
+          implements NavigableMap<K,V>, Serializable {
+        private static final long serialVersionUID = -4858195264774772197L;
+
+        /**
+         * A class for the {@link EMPTY_NAVIGABLE_MAP} which needs readResolve
+         * to preserve singleton property.
+         *
+         * @param <K> type of keys, if there were any, and of bounds
+         * @param <V> type of values, if there were any
+         */
+        private static class EmptyNavigableMap<K,V> extends UnmodifiableNavigableMap<K,V>
+            implements Serializable {
+
+            private static final long serialVersionUID = -2239321462712562324L;
+
+            EmptyNavigableMap()                       { super(new TreeMap()); }
+
+            @Override
+            public NavigableSet<K> navigableKeySet()
+                                                { return emptyNavigableSet(); }
+
+            private Object readResolve()        { return EMPTY_NAVIGABLE_MAP; }
         }
-        public SortedMap<K,V> headMap(K toKey) {
-            return new UnmodifiableSortedMap<>(sm.headMap(toKey));
+
+        /**
+         * Singleton for {@link emptyNavigableMap()} which is also immutable.
+         */
+        private static final EmptyNavigableMap<?,?> EMPTY_NAVIGABLE_MAP =
+            new EmptyNavigableMap<>();
+
+        /**
+         * The instance we wrap and protect.
+         */
+        private final NavigableMap<K, ? extends V> nm;
+
+        UnmodifiableNavigableMap(NavigableMap<K, ? extends V> m)
+                                                            {super(m); nm = m;}
+
+        public K lowerKey(K key)                   { return nm.lowerKey(key); }
+        public K floorKey(K key)                   { return nm.floorKey(key); }
+        public K ceilingKey(K key)               { return nm.ceilingKey(key); }
+        public K higherKey(K key)                 { return nm.higherKey(key); }
+
+        public Entry<K, V> lowerEntry(K key) {
+            Entry<K,V> lower = (Entry<K, V>) nm.lowerEntry(key);
+            return (null != lower)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(lower)
+                : null;
         }
-        public SortedMap<K,V> tailMap(K fromKey) {
-            return new UnmodifiableSortedMap<>(sm.tailMap(fromKey));
+
+        public Entry<K, V> floorEntry(K key) {
+            Entry<K,V> floor = (Entry<K, V>) nm.floorEntry(key);
+            return (null != floor)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(floor)
+                : null;
         }
 
-        public K firstKey()           {return sm.firstKey();}
-        public K lastKey()            {return sm.lastKey();}
-    }
+        public Entry<K, V> ceilingEntry(K key) {
+            Entry<K,V> ceiling = (Entry<K, V>) nm.ceilingEntry(key);
+            return (null != ceiling)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(ceiling)
+                : null;
+        }
+
+
+        public Entry<K, V> higherEntry(K key) {
+            Entry<K,V> higher = (Entry<K, V>) nm.higherEntry(key);
+            return (null != higher)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(higher)
+                : null;
+        }
+
+        public Entry<K, V> firstEntry() {
+            Entry<K,V> first = (Entry<K, V>) nm.firstEntry();
+            return (null != first)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(first)
+                : null;
+        }
+
+        public Entry<K, V> lastEntry() {
+            Entry<K,V> last = (Entry<K, V>) nm.lastEntry();
+            return (null != last)
+                ? new UnmodifiableEntrySet.UnmodifiableEntry(last)
+                : null;
+        }
+
+        public Entry<K, V> pollFirstEntry()
+                                 { throw new UnsupportedOperationException(); }
+        public Entry<K, V> pollLastEntry()
+                                 { throw new UnsupportedOperationException(); }
+        public NavigableMap<K, V> descendingMap()
+                       { return unmodifiableNavigableMap(nm.descendingMap()); }
+        public NavigableSet<K> navigableKeySet()
+                     { return unmodifiableNavigableSet(nm.navigableKeySet()); }
+        public NavigableSet<K> descendingKeySet()
+                    { return unmodifiableNavigableSet(nm.descendingKeySet()); }
 
+        public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
+            return unmodifiableNavigableMap(
+                nm.subMap(fromKey, fromInclusive, toKey, toInclusive));
+        }
+
+        public NavigableMap<K, V> headMap(K toKey, boolean inclusive)
+             { return unmodifiableNavigableMap(nm.headMap(toKey, inclusive)); }
+        public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive)
+           { return unmodifiableNavigableMap(nm.tailMap(fromKey, inclusive)); }
+    }
 
     // Synch Wrappers
 
@@ -1805,14 +2023,13 @@ public class Collections {
         final Object mutex;     // Object on which to synchronize
 
         SynchronizedCollection(Collection<E> c) {
-            if (c==null)
-                throw new NullPointerException();
-            this.c = c;
+            this.c = Objects.requireNonNull(c);
             mutex = this;
         }
+
         SynchronizedCollection(Collection<E> c, Object mutex) {
-            this.c = c;
-            this.mutex = mutex;
+            this.c = Objects.requireNonNull(c);
+            this.mutex = Objects.requireNonNull(mutex);
         }
 
         public int size() {
@@ -2026,6 +2243,120 @@ public class Collections {
         }
     }
 
+    /**
+     * Returns a synchronized (thread-safe) navigable set backed by the
+     * specified navigable set.  In order to guarantee serial access, it is
+     * critical that <strong>all</strong> access to the backing navigable set is
+     * accomplished through the returned navigable set (or its views).<p>
+     *
+     * It is imperative that the user manually synchronize on the returned
+     * navigable set when iterating over it or any of its {@code subSet},
+     * {@code headSet}, or {@code tailSet} views.
+     * <pre>
+     *  NavigableSet s = Collections.synchronizedNavigableSet(new TreeSet());
+     *      ...
+     *  synchronized (s) {
+     *      Iterator i = s.iterator(); // Must be in the synchronized block
+     *      while (i.hasNext())
+     *          foo(i.next());
+     *  }
+     * </pre>
+     * or:
+     * <pre>
+     *  NavigableSet s = Collections.synchronizedNavigableSet(new TreeSet());
+     *  NavigableSet s2 = s.headSet(foo, true);
+     *      ...
+     *  synchronized (s) {  // Note: s, not s2!!!
+     *      Iterator i = s2.iterator(); // Must be in the synchronized block
+     *      while (i.hasNext())
+     *          foo(i.next());
+     *  }
+     * </pre>
+     * Failure to follow this advice may result in non-deterministic behavior.
+     *
+     * <p>The returned navigable set will be serializable if the specified
+     * navigable set is serializable.
+     *
+     * @param  s the navigable set to be "wrapped" in a synchronized navigable
+     * set
+     * @return a synchronized view of the specified navigable set
+     * @since 1.8
+     */
+    public static <T> NavigableSet<T> synchronizedNavigableSet(NavigableSet<T> s) {
+        return new SynchronizedNavigableSet<>(s);
+    }
+
+    /**
+     * @serial include
+     */
+    static class SynchronizedNavigableSet<E>
+        extends SynchronizedSortedSet<E>
+        implements NavigableSet<E>
+    {
+        private static final long serialVersionUID = -5505529816273629798L;
+
+        private final NavigableSet<E> ns;
+
+        SynchronizedNavigableSet(NavigableSet<E> s) {
+            super(s);
+            ns = s;
+        }
+
+        SynchronizedNavigableSet(NavigableSet<E> s, Object mutex) {
+            super(s, mutex);
+            ns = s;
+        }
+        public E lower(E e)      { synchronized (mutex) {return ns.lower(e);} }
+        public E floor(E e)      { synchronized (mutex) {return ns.floor(e);} }
+        public E ceiling(E e)  { synchronized (mutex) {return ns.ceiling(e);} }
+        public E higher(E e)    { synchronized (mutex) {return ns.higher(e);} }
+        public E pollFirst()  { synchronized (mutex) {return ns.pollFirst();} }
+        public E pollLast()    { synchronized (mutex) {return ns.pollLast();} }
+
+        public NavigableSet<E> descendingSet() {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.descendingSet(), mutex);
+            }
+        }
+
+        public Iterator<E> descendingIterator()
+                 { synchronized (mutex) { return descendingSet().iterator(); } }
+
+        public NavigableSet<E> subSet(E fromElement, E toElement) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.subSet(fromElement, true, toElement, false), mutex);
+            }
+        }
+        public NavigableSet<E> headSet(E toElement) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.headSet(toElement, false), mutex);
+            }
+        }
+        public NavigableSet<E> tailSet(E fromElement) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet(ns.tailSet(fromElement, true), mutex);
+            }
+        }
+
+        public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.subSet(fromElement, fromInclusive, toElement, toInclusive), mutex);
+            }
+        }
+
+        public NavigableSet<E> headSet(E toElement, boolean inclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.headSet(toElement, inclusive), mutex);
+            }
+        }
+
+        public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet<>(ns.tailSet(fromElement, inclusive));
+            }
+        }
+    }
+
     /**
      * Returns a synchronized (thread-safe) list backed by the specified
      * list.  In order to guarantee serial access, it is critical that
@@ -2235,9 +2566,7 @@ public class Collections {
         final Object      mutex;        // Object on which to synchronize
 
         SynchronizedMap(Map<K,V> m) {
-            if (m==null)
-                throw new NullPointerException();
-            this.m = m;
+            this.m = Objects.requireNonNull(m);
             mutex = this;
         }
 
@@ -2416,7 +2745,6 @@ public class Collections {
         return new SynchronizedSortedMap<>(m);
     }
 
-
     /**
      * @serial include
      */
@@ -2466,6 +2794,164 @@ public class Collections {
         }
     }
 
+    /**
+     * Returns a synchronized (thread-safe) navigable map backed by the
+     * specified navigable map.  In order to guarantee serial access, it is
+     * critical that <strong>all</strong> access to the backing navigable map is
+     * accomplished through the returned navigable map (or its views).<p>
+     *
+     * It is imperative that the user manually synchronize on the returned
+     * navigable map when iterating over any of its collection views, or the
+     * collections views of any of its {@code subMap}, {@code headMap} or
+     * {@code tailMap} views.
+     * <pre>
+     *  NavigableMap m = Collections.synchronizedNavigableMap(new TreeMap());
+     *      ...
+     *  Set s = m.keySet();  // Needn't be in synchronized block
+     *      ...
+     *  synchronized (m) {  // Synchronizing on m, not s!
+     *      Iterator i = s.iterator(); // Must be in synchronized block
+     *      while (i.hasNext())
+     *          foo(i.next());
+     *  }
+     * </pre>
+     * or:
+     * <pre>
+     *  NavigableMap m = Collections.synchronizedNavigableMap(new TreeMap());
+     *  NavigableMap m2 = m.subMap(foo, true, bar, false);
+     *      ...
+     *  Set s2 = m2.keySet();  // Needn't be in synchronized block
+     *      ...
+     *  synchronized (m) {  // Synchronizing on m, not m2 or s2!
+     *      Iterator i = s.iterator(); // Must be in synchronized block
+     *      while (i.hasNext())
+     *          foo(i.next());
+     *  }
+     * </pre>
+     * Failure to follow this advice may result in non-deterministic behavior.
+     *
+     * <p>The returned navigable map will be serializable if the specified
+     * navigable map is serializable.
+     *
+     * @param  m the navigable map to be "wrapped" in a synchronized navigable
+     *              map
+     * @return a synchronized view of the specified navigable map.
+     * @since 1.8
+     */
+    public static <K,V> NavigableMap<K,V> synchronizedNavigableMap(NavigableMap<K,V> m) {
+        return new SynchronizedNavigableMap<>(m);
+    }
+
+    /**
+     * A synchronized NavigableMap.
+     *
+     * @serial include
+     */
+    static class SynchronizedNavigableMap<K,V>
+        extends SynchronizedSortedMap<K,V>
+        implements NavigableMap<K,V>
+    {
+        private static final long serialVersionUID = 699392247599746807L;
+
+        private final NavigableMap<K,V> nm;
+
+        SynchronizedNavigableMap(NavigableMap<K,V> m) {
+            super(m);
+            nm = m;
+        }
+        SynchronizedNavigableMap(NavigableMap<K,V> m, Object mutex) {
+            super(m, mutex);
+            nm = m;
+        }
+
+        public Entry<K, V> lowerEntry(K key)
+                        { synchronized (mutex) { return nm.lowerEntry(key); } }
+        public K lowerKey(K key)
+                          { synchronized (mutex) { return nm.lowerKey(key); } }
+        public Entry<K, V> floorEntry(K key)
+                        { synchronized (mutex) { return nm.floorEntry(key); } }
+        public K floorKey(K key)
+                          { synchronized (mutex) { return nm.floorKey(key); } }
+        public Entry<K, V> ceilingEntry(K key)
+                      { synchronized (mutex) { return nm.ceilingEntry(key); } }
+        public K ceilingKey(K key)
+                        { synchronized (mutex) { return nm.ceilingKey(key); } }
+        public Entry<K, V> higherEntry(K key)
+                       { synchronized (mutex) { return nm.higherEntry(key); } }
+        public K higherKey(K key)
+                         { synchronized (mutex) { return nm.higherKey(key); } }
+        public Entry<K, V> firstEntry()
+                           { synchronized (mutex) { return nm.firstEntry(); } }
+        public Entry<K, V> lastEntry()
+                            { synchronized (mutex) { return nm.lastEntry(); } }
+        public Entry<K, V> pollFirstEntry()
+                       { synchronized (mutex) { return nm.pollFirstEntry(); } }
+        public Entry<K, V> pollLastEntry()
+                        { synchronized (mutex) { return nm.pollLastEntry(); } }
+
+        public NavigableMap<K, V> descendingMap() {
+            synchronized (mutex) {
+                return
+                    new SynchronizedNavigableMap(nm.descendingMap(), mutex);
+            }
+        }
+
+        public NavigableSet<K> keySet() {
+            return navigableKeySet();
+        }
+
+        public NavigableSet<K> navigableKeySet() {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet(nm.navigableKeySet(), mutex);
+            }
+        }
+
+        public NavigableSet<K> descendingKeySet() {
+            synchronized (mutex) {
+                return new SynchronizedNavigableSet(nm.descendingKeySet(), mutex);
+            }
+        }
+
+
+        public SortedMap<K,V> subMap(K fromKey, K toKey) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableMap<>(
+                    nm.subMap(fromKey, true, toKey, false), mutex);
+            }
+        }
+        public SortedMap<K,V> headMap(K toKey) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableMap<>(nm.headMap(toKey, false), mutex);
+            }
+        }
+        public SortedMap<K,V> tailMap(K fromKey) {
+            synchronized (mutex) {
+               return new SynchronizedNavigableMap<>(nm.tailMap(fromKey, true),mutex);
+            }
+        }
+
+        public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableMap(
+                    nm.subMap(fromKey, fromInclusive, toKey, toInclusive), mutex);
+            }
+        }
+
+        public NavigableMap<K, V> headMap(K toKey, boolean inclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableMap(
+                        nm.headMap(toKey, inclusive), mutex);
+            }
+        }
+
+        public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
+            synchronized (mutex) {
+                return new SynchronizedNavigableMap(
+                    nm.tailMap(fromKey, inclusive), mutex);
+            }
+        }
+    }
+
     // Dynamically typesafe collection wrappers
 
     /**
@@ -2497,12 +2983,12 @@ public class Collections {
      * program to wrap the collection with a dynamically typesafe view.
      * For example, this declaration:
      *  <pre> {@code
-     *     Collection<String> c = new HashSet<String>();
+     *     Collection<String> c = new HashSet<>();
      * }</pre>
      * may be replaced temporarily by this one:
      *  <pre> {@code
      *     Collection<String> c = Collections.checkedCollection(
-     *         new HashSet<String>(), String.class);
+     *         new HashSet<>(), String.class);
      * }</pre>
      * Running the program again will cause it to fail at the point where
      * an incorrectly typed element is inserted into the collection, clearly
@@ -2788,6 +3274,7 @@ public class Collections {
         implements SortedSet<E>, Serializable
     {
         private static final long serialVersionUID = 1599911165492914959L;
+
         private final SortedSet<E> ss;
 
         CheckedSortedSet(SortedSet<E> s, Class<E> type) {
@@ -2810,6 +3297,87 @@ public class Collections {
         }
     }
 
+/**
+     * Returns a dynamically typesafe view of the specified navigable set.
+     * Any attempt to insert an element of the wrong type will result in an
+     * immediate {@link ClassCastException}.  Assuming a navigable set
+     * contains no incorrectly typed elements prior to the time a
+     * dynamically typesafe view is generated, and that all subsequent
+     * access to the navigable set takes place through the view, it is
+     * <em>guaranteed</em> that the navigable set cannot contain an incorrectly
+     * typed element.
+     *
+     * <p>A discussion of the use of dynamically typesafe views may be
+     * found in the documentation for the {@link #checkedCollection
+     * checkedCollection} method.
+     *
+     * <p>The returned navigable set will be serializable if the specified
+     * navigable set is serializable.
+     *
+     * <p>Since {@code null} is considered to be a value of any reference
+     * type, the returned navigable set permits insertion of null elements
+     * whenever the backing sorted set does.
+     *
+     * @param s the navigable set for which a dynamically typesafe view is to be
+     *          returned
+     * @param type the type of element that {@code s} is permitted to hold
+     * @return a dynamically typesafe view of the specified navigable set
+     * @since 1.8
+     */
+    public static <E> NavigableSet<E> checkedNavigableSet(NavigableSet<E> s,
+                                                    Class<E> type) {
+        return new CheckedNavigableSet<>(s, type);
+    }
+
+    /**
+     * @serial include
+     */
+    static class CheckedNavigableSet<E> extends CheckedSortedSet<E>
+        implements NavigableSet<E>, Serializable
+    {
+        private static final long serialVersionUID = -5429120189805438922L;
+
+        private final NavigableSet<E> ns;
+
+        CheckedNavigableSet(NavigableSet<E> s, Class<E> type) {
+            super(s, type);
+            ns = s;
+        }
+
+        public E lower(E e)                             { return ns.lower(e); }
+        public E floor(E e)                             { return ns.floor(e); }
+        public E ceiling(E e)                         { return ns.ceiling(e); }
+        public E higher(E e)                           { return ns.higher(e); }
+        public E pollFirst()                         { return ns.pollFirst(); }
+        public E pollLast()                            {return ns.pollLast(); }
+        public NavigableSet<E> descendingSet()
+                      { return checkedNavigableSet(ns.descendingSet(), type); }
+        public Iterator<E> descendingIterator()
+            {return checkedNavigableSet(ns.descendingSet(), type).iterator(); }
+
+        public NavigableSet<E> subSet(E fromElement, E toElement) {
+            return checkedNavigableSet(ns.subSet(fromElement, true, toElement, false), type);
+        }
+        public NavigableSet<E> headSet(E toElement) {
+            return checkedNavigableSet(ns.headSet(toElement, false), type);
+        }
+        public NavigableSet<E> tailSet(E fromElement) {
+            return checkedNavigableSet(ns.tailSet(fromElement, true), type);
+        }
+
+        public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
+            return checkedNavigableSet(ns.subSet(fromElement, fromInclusive, toElement, toInclusive), type);
+        }
+
+        public NavigableSet<E> headSet(E toElement, boolean inclusive) {
+            return checkedNavigableSet(ns.headSet(toElement, inclusive), type);
+        }
+
+        public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
+            return checkedNavigableSet(ns.tailSet(fromElement, inclusive), type);
+        }
+    }
+
     /**
      * Returns a dynamically typesafe view of the specified list.
      * Any attempt to insert an element of the wrong type will result in
@@ -3022,11 +3590,9 @@ public class Collections {
         }
 
         CheckedMap(Map<K, V> m, Class<K> keyType, Class<V> valueType) {
-            if (m == null || keyType == null || valueType == null)
-                throw new NullPointerException();
-            this.m = m;
-            this.keyType = keyType;
-            this.valueType = valueType;
+            this.m = Objects.requireNonNull(m);
+            this.keyType = Objects.requireNonNull(keyType);
+            this.valueType = Objects.requireNonNull(valueType);
         }
 
         public int size()                      { return m.size(); }
@@ -3303,8 +3869,8 @@ public class Collections {
                 private final Class<T> valueType;
 
                 CheckedEntry(Map.Entry<K, V> e, Class<T> valueType) {
-                    this.e = e;
-                    this.valueType = valueType;
+                    this.e = Objects.requireNonNull(e);
+                    this.valueType = Objects.requireNonNull(valueType);
                 }
 
                 public K getKey()        { return e.getKey(); }
@@ -3407,6 +3973,177 @@ public class Collections {
         }
     }
 
+    /**
+     * Returns a dynamically typesafe view of the specified navigable map.
+     * Any attempt to insert a mapping whose key or value have the wrong
+     * type will result in an immediate {@link ClassCastException}.
+     * Similarly, any attempt to modify the value currently associated with
+     * a key will result in an immediate {@link ClassCastException},
+     * whether the modification is attempted directly through the map
+     * itself, or through a {@link Map.Entry} instance obtained from the
+     * map's {@link Map#entrySet() entry set} view.
+     *
+     * <p>Assuming a map contains no incorrectly typed keys or values
+     * prior to the time a dynamically typesafe view is generated, and
+     * that all subsequent access to the map takes place through the view
+     * (or one of its collection views), it is <em>guaranteed</em> that the
+     * map cannot contain an incorrectly typed key or value.
+     *
+     * <p>A discussion of the use of dynamically typesafe views may be
+     * found in the documentation for the {@link #checkedCollection
+     * checkedCollection} method.
+     *
+     * <p>The returned map will be serializable if the specified map is
+     * serializable.
+     *
+     * <p>Since {@code null} is considered to be a value of any reference
+     * type, the returned map permits insertion of null keys or values
+     * whenever the backing map does.
+     *
+     * @param <K> type of map keys
+     * @param <V> type of map values
+     * @param m the map for which a dynamically typesafe view is to be
+     *          returned
+     * @param keyType the type of key that {@code m} is permitted to hold
+     * @param valueType the type of value that {@code m} is permitted to hold
+     * @return a dynamically typesafe view of the specified map
+     * @since 1.8
+     */
+    public static <K,V> NavigableMap<K,V> checkedNavigableMap(NavigableMap<K, V> m,
+                                                        Class<K> keyType,
+                                                        Class<V> valueType) {
+        return new CheckedNavigableMap<>(m, keyType, valueType);
+    }
+
+    /**
+     * @serial include
+     */
+    static class CheckedNavigableMap<K,V> extends CheckedSortedMap<K,V>
+        implements NavigableMap<K,V>, Serializable
+    {
+        private static final long serialVersionUID = -4852462692372534096L;
+
+        private final NavigableMap<K, V> nm;
+
+        CheckedNavigableMap(NavigableMap<K, V> m,
+                         Class<K> keyType, Class<V> valueType) {
+            super(m, keyType, valueType);
+            nm = m;
+        }
+
+        public Comparator<? super K> comparator()   { return nm.comparator(); }
+        public K firstKey()                           { return nm.firstKey(); }
+        public K lastKey()                             { return nm.lastKey(); }
+
+        public Entry<K, V> lowerEntry(K key) {
+            Entry<K,V> lower = nm.lowerEntry(key);
+            return (null != lower)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(lower, valueType)
+                : null;
+        }
+
+        public K lowerKey(K key)                   { return nm.lowerKey(key); }
+
+        public Entry<K, V> floorEntry(K key) {
+            Entry<K,V> floor = nm.floorEntry(key);
+            return (null != floor)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(floor, valueType)
+                : null;
+        }
+
+        public K floorKey(K key)                   { return nm.floorKey(key); }
+
+        public Entry<K, V> ceilingEntry(K key) {
+            Entry<K,V> ceiling = nm.ceilingEntry(key);
+            return (null != ceiling)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(ceiling, valueType)
+                : null;
+        }
+
+        public K ceilingKey(K key)               { return nm.ceilingKey(key); }
+
+        public Entry<K, V> higherEntry(K key) {
+            Entry<K,V> higher = nm.higherEntry(key);
+            return (null != higher)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(higher, valueType)
+                : null;
+        }
+
+        public K higherKey(K key)                 { return nm.higherKey(key); }
+
+        public Entry<K, V> firstEntry() {
+            Entry<K,V> first = nm.firstEntry();
+            return (null != first)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(first, valueType)
+                : null;
+        }
+
+        public Entry<K, V> lastEntry() {
+            Entry<K,V> last = nm.lastEntry();
+            return (null != last)
+                ? new CheckedMap.CheckedEntrySet.CheckedEntry(last, valueType)
+                : null;
+        }
+
+        public Entry<K, V> pollFirstEntry() {
+            Entry<K,V> entry = nm.pollFirstEntry();
+            return (null == entry)
+                ? null
+                : new CheckedMap.CheckedEntrySet.CheckedEntry(entry, valueType);
+        }
+
+        public Entry<K, V> pollLastEntry() {
+            Entry<K,V> entry = nm.pollLastEntry();
+            return (null == entry)
+                ? null
+                : new CheckedMap.CheckedEntrySet.CheckedEntry(entry, valueType);
+        }
+
+        public NavigableMap<K, V> descendingMap() {
+            return checkedNavigableMap(nm.descendingMap(), keyType, valueType);
+        }
+
+        public NavigableSet<K> keySet() {
+            return navigableKeySet();
+        }
+
+        public NavigableSet<K> navigableKeySet() {
+            return checkedNavigableSet(nm.navigableKeySet(), keyType);
+        }
+
+        public NavigableSet<K> descendingKeySet() {
+            return checkedNavigableSet(nm.descendingKeySet(), keyType);
+        }
+
+        @Override
+        public NavigableMap<K,V> subMap(K fromKey, K toKey) {
+            return checkedNavigableMap(nm.subMap(fromKey, true, toKey, false),
+                                    keyType, valueType);
+        }
+
+        @Override
+        public NavigableMap<K,V> headMap(K toKey) {
+            return checkedNavigableMap(nm.headMap(toKey, false), keyType, valueType);
+        }
+
+        @Override
+        public NavigableMap<K,V> tailMap(K fromKey) {
+            return checkedNavigableMap(nm.tailMap(fromKey, true), keyType, valueType);
+        }
+
+        public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
+            return checkedNavigableMap(nm.subMap(fromKey, fromInclusive, toKey, toInclusive), keyType, valueType);
+        }
+
+        public NavigableMap<K, V> headMap(K toKey, boolean inclusive) {
+            return checkedNavigableMap(nm.headMap(toKey, inclusive), keyType, valueType);
+        }
+
+        public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
+            return checkedNavigableMap(nm.tailMap(fromKey, inclusive), keyType, valueType);
+        }
+    }
+
     // Empty collections
 
     /**
@@ -3428,6 +4165,7 @@ public class Collections {
      * <p>Implementations of this method are permitted, but not
      * required, to return the same object from multiple invocations.
      *
+     * @param <T> type of elements, if there were any, in the iterator
      * @return an empty iterator
      * @since 1.7
      */
@@ -3478,6 +4216,7 @@ public class Collections {
      * <p>Implementations of this method are permitted, but not
      * required, to return the same object from multiple invocations.
      *
+     * @param <T> type of elements, if there were any, in the iterator
      * @return an empty list iterator
      * @since 1.7
      */
@@ -3542,17 +4281,19 @@ public class Collections {
     public static final Set EMPTY_SET = new EmptySet<>();
 
     /**
-     * Returns the empty set (immutable).  This set is serializable.
+     * Returns an empty set (immutable).  This set is serializable.
      * Unlike the like-named field, this method is parameterized.
      *
      * <p>This example illustrates the type-safe way to obtain an empty set:
      * <pre>
      *     Set&lt;String&gt; s = Collections.emptySet();
      * </pre>
-     * Implementation note:  Implementations of this method need not
-     * create a separate <tt>Set</tt> object for each call.   Using this
-     * method is likely to have comparable cost to using the like-named
-     * field.  (Unlike this method, the field does not provide type safety.)
+     * @implNote Implementations of this method need not create a separate
+     * {@code Set} object for each call.  Using this method is likely to have
+     * comparable cost to using the like-named field.  (Unlike this method, the
+     * field does not provide type safety.)
+     *
+     * @return the empty set
      *
      * @see #EMPTY_SET
      * @since 1.5
@@ -3607,121 +4348,45 @@ public class Collections {
     }
 
     /**
-     * Returns the empty sorted set (immutable).  This set is serializable.
+     * Returns an empty sorted set (immutable).  This set is serializable.
      *
-     * <p>This example illustrates the type-safe way to obtain an empty sorted
-     * set:
-     * <pre>
-     *     SortedSet&lt;String&gt; s = Collections.emptySortedSet();
-     * </pre>
-     * Implementation note:  Implementations of this method need not
-     * create a separate <tt>SortedSet</tt> object for each call.
+     * <p>This example illustrates the type-safe way to obtain an empty
+     * sorted set:
+     * <pre> {@code
+     *     SortedSet<String> s = Collections.emptySortedSet();
+     * }</pre>
      *
+     * @implNote Implementations of this method need not create a separate
+     * {@code SortedSet} object for each call.
+     *
+     * @param <E> type of elements, if there were any, in the set
+     * @return the empty sorted set
      * @since 1.8
      */
     @SuppressWarnings("unchecked")
-    public static final <E> SortedSet<E> emptySortedSet() {
-        return (SortedSet<E>) new EmptySortedSet<>();
+    public static <E> SortedSet<E> emptySortedSet() {
+        return (SortedSet<E>) UnmodifiableNavigableSet.EMPTY_NAVIGABLE_SET;
     }
 
     /**
-     * @serial include
+     * Returns an empty navigable set (immutable).  This set is serializable.
+     *
+     * <p>This example illustrates the type-safe way to obtain an empty
+     * navigable set:
+     * <pre> {@code
+     *     NavigableSet<String> s = Collections.emptyNavigableSet();
+     * }</pre>
+     *
+     * @implNote Implementations of this method need not
+     * create a separate {@code NavigableSet} object for each call.
+     *
+     * @param <E> type of elements, if there were any, in the set
+     * @return the empty navigable set
+     * @since 1.8
      */
-    private static class EmptySortedSet<E>
-        extends AbstractSet<E>
-        implements SortedSet<E>, Serializable
-    {
-        private static final long serialVersionUID = 6316515401502265487L;
-        public Iterator<E> iterator() { return emptyIterator(); }
-        public int size() {return 0;}
-        public boolean isEmpty() {return true;}
-        public boolean contains(Object obj) {return false;}
-        public boolean containsAll(Collection<?> c) { return c.isEmpty(); }
-        public Object[] toArray() { return new Object[0]; }
-
-        public <E> E[] toArray(E[] a) {
-            if (a.length > 0)
-                a[0] = null;
-            return a;
-        }
-
-        // Preserves singleton property
-        private Object readResolve() {
-            return new EmptySortedSet<>();
-        }
-
-        @Override
-        public Comparator<? super E> comparator() {
-            return null;
-        }
-
-        @Override
-        @SuppressWarnings("unchecked")
-        public SortedSet<E> subSet(Object fromElement, Object toElement) {
-            Objects.requireNonNull(fromElement);
-            Objects.requireNonNull(toElement);
-
-            if (!(fromElement instanceof Comparable) ||
-                    !(toElement instanceof Comparable))
-            {
-                throw new ClassCastException();
-            }
-
-            if ((((Comparable)fromElement).compareTo(toElement) >= 0) ||
-                    (((Comparable)toElement).compareTo(fromElement) < 0))
-            {
-                throw new IllegalArgumentException();
-            }
-
-            return emptySortedSet();
-        }
-
-        @Override
-        public SortedSet<E> headSet(Object toElement) {
-            Objects.requireNonNull(toElement);
-
-            if (!(toElement instanceof Comparable)) {
-                throw new ClassCastException();
-            }
-
-            return emptySortedSet();
-        }
-
-        @Override
-        public SortedSet<E> tailSet(Object fromElement) {
-            Objects.requireNonNull(fromElement);
-
-            if (!(fromElement instanceof Comparable)) {
-                throw new ClassCastException();
-            }
-
-            return emptySortedSet();
-        }
-
-        @Override
-        public E first() {
-            throw new NoSuchElementException();
-        }
-
-        @Override
-        public E last() {
-            throw new NoSuchElementException();
-        }
-
-        // Override default methods in Collection
-        @Override
-        public void forEach(Consumer<? super E> action) {
-            Objects.requireNonNull(action);
-        }
-
-        @Override
-        public boolean removeIf(Predicate<? super E> filter) {
-            Objects.requireNonNull(filter);
-            return false;
-        }
-
-        @Override
-        public Spliterator<E> spliterator() { return Spliterators.emptySpliterator(); }
+    @SuppressWarnings("unchecked")
+    public static <E> NavigableSet<E> emptyNavigableSet() {
+        return (NavigableSet<E>) UnmodifiableNavigableSet.EMPTY_NAVIGABLE_SET;
     }
 
     /**
@@ -3733,7 +4398,7 @@ public class Collections {
     public static final List EMPTY_LIST = new EmptyList<>();
 
     /**
-     * Returns the empty list (immutable).  This list is serializable.
+     * Returns an empty list (immutable).  This list is serializable.
      *
      * <p>This example illustrates the type-safe way to obtain an empty list:
      * <pre>
@@ -3744,6 +4409,9 @@ public class Collections {
      * method is likely to have comparable cost to using the like-named
      * field.  (Unlike this method, the field does not provide type safety.)
      *
+     * @param <T> type of elements, if there were any, in the list
+     * @return an empty immutable list
+     *
      * @see #EMPTY_LIST
      * @since 1.5
      */
@@ -3830,17 +4498,18 @@ public class Collections {
     public static final Map EMPTY_MAP = new EmptyMap<>();
 
     /**
-     * Returns the empty map (immutable).  This map is serializable.
+     * Returns an empty map (immutable).  This map is serializable.
      *
-     * <p>This example illustrates the type-safe way to obtain an empty set:
+     * <p>This example illustrates the type-safe way to obtain an empty map:
      * <pre>
      *     Map&lt;String, Date&gt; s = Collections.emptyMap();
      * </pre>
-     * Implementation note:  Implementations of this method need not
-     * create a separate <tt>Map</tt> object for each call.   Using this
-     * method is likely to have comparable cost to using the like-named
-     * field.  (Unlike this method, the field does not provide type safety.)
+     * @implNote Implementations of this method need not create a separate
+     * {@code Map} object for each call.  Using this method is likely to have
+     * comparable cost to using the like-named field.  (Unlike this method, the
+     * field does not provide type safety.)
      *
+     * @return an empty map
      * @see #EMPTY_MAP
      * @since 1.5
      */
@@ -3849,6 +4518,44 @@ public class Collections {
         return (Map<K,V>) EMPTY_MAP;
     }
 
+    /**
+     * Returns an empty sorted map (immutable).  This map is serializable.
+     *
+     * <p>This example illustrates the type-safe way to obtain an empty map:
+     * <pre> {@code
+     *     SortedMap<String, Date> s = Collections.emptySortedMap();
+     * }</pre>
+     *
+     * @implNote Implementations of this method need not create a separate
+     * {@code SortedMap} object for each call.
+     *
+     * @return an empty sorted map
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static final <K,V> SortedMap<K,V> emptySortedMap() {
+        return (SortedMap<K,V>) UnmodifiableNavigableMap.EMPTY_NAVIGABLE_MAP;
+    }
+
+    /**
+     * Returns an empty navigable map (immutable).  This map is serializable.
+     *
+     * <p>This example illustrates the type-safe way to obtain an empty map:
+     * <pre> {@code
+     *     NavigableMap<String, Date> s = Collections.emptyNavigableMap();
+     * }</pre>
+     *
+     * @implNote Implementations of this method need not create a separate
+     * {@code NavigableMap} object for each call.
+     *
+     * @return an empty navigable map
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static final <K,V> NavigableMap<K,V> emptyNavigableMap() {
+        return (NavigableMap<K,V>) UnmodifiableNavigableMap.EMPTY_NAVIGABLE_MAP;
+    }
+
     /**
      * @serial include
      */
@@ -4153,15 +4860,11 @@ public class Collections {
             v = value;
         }
 
-        public int size()                          {return 1;}
-
-        public boolean isEmpty()                   {return false;}
-
-        public boolean containsKey(Object key)     {return eq(key, k);}
-
-        public boolean containsValue(Object value) {return eq(value, v);}
-
-        public V get(Object key)                   {return (eq(key, k) ? v : null);}
+        public int size()                                           {return 1;}
+        public boolean isEmpty()                                {return false;}
+        public boolean containsKey(Object key)             {return eq(key, k);}
+        public boolean containsValue(Object value)       {return eq(value, v);}
+        public V get(Object key)              {return (eq(key, k) ? v : null);}
 
         private transient Set<K> keySet = null;
         private transient Set<Map.Entry<K,V>> entrySet = null;
@@ -4508,6 +5211,8 @@ public class Collections {
 
     /**
      * Returns true if the specified arguments are equal, or both null.
+     *
+     * NB: Do not replace with Object.equals until JDK-8015417 is resolved.
      */
     static boolean eq(Object o1, Object o2) {
         return o1==null ? o2==null : o1.equals(o2);
diff --git a/src/share/classes/java/util/NavigableSet.java b/src/share/classes/java/util/NavigableSet.java
index 26fcd3a7c35fb79166ba186b971553b1a079ea61..4dbb1c1cc454427ee0e7df5ae91e399f821c68e8 100644
--- a/src/share/classes/java/util/NavigableSet.java
+++ b/src/share/classes/java/util/NavigableSet.java
@@ -303,7 +303,7 @@ public interface NavigableSet<E> extends SortedSet<E> {
      * @throws ClassCastException       {@inheritDoc}
      * @throws NullPointerException     {@inheritDoc}
      * @throws IllegalArgumentException {@inheritDoc}
-na     */
+     */
     SortedSet<E> headSet(E toElement);
 
     /**
diff --git a/src/share/classes/java/util/Optional.java b/src/share/classes/java/util/Optional.java
index b51a4d261221383207e353e606c5f7c600770623..4e95e18684b335f7a82986a6f6b186fa9ad6a6fc 100644
--- a/src/share/classes/java/util/Optional.java
+++ b/src/share/classes/java/util/Optional.java
@@ -25,6 +25,8 @@
 package java.util;
 
 import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
 import java.util.function.Supplier;
 
 /**
@@ -52,7 +54,7 @@ public final class Optional<T> {
     private final T value;
 
     /**
-     * Construct an empty instance.
+     * Constructs an empty instance.
      *
      * @implNote Generally only one empty instance, {@link Optional#EMPTY},
      * should exist per VM.
@@ -80,7 +82,7 @@ public final class Optional<T> {
     }
 
     /**
-     * Construct an instance with the value present.
+     * Constructs an instance with the value present.
      *
      * @param value the non-null value to be present
      */
@@ -89,7 +91,7 @@ public final class Optional<T> {
     }
 
     /**
-     * Return an {@code Optional} with the specified present value.
+     * Returns an {@code Optional} with the specified present non-null value.
      *
      * @param value the value to be present, which must be non-null
      * @return an {@code Optional} with the value present
@@ -98,6 +100,18 @@ public final class Optional<T> {
         return new Optional<>(value);
     }
 
+    /**
+     * Returns an {@code Optional} describing the specified value, if non-null,
+     * otherwise returns an empty {@code Optional}.
+     *
+     * @param value the possibly-null value to describe
+     * @return an {@code Optional} with a present value if the specified value
+     * is non-null, otherwise an empty {@code Optional}
+     */
+    public static <T> Optional<T> ofNullable(T value) {
+        return value == null ? empty() : of(value);
+    }
+
     /**
      * If a value is present in this {@code Optional}, returns the value,
      * otherwise throws {@code NoSuchElementException}.
@@ -124,7 +138,7 @@ public final class Optional<T> {
     }
 
     /**
-     * Have the specified consumer accept the value if a value is present,
+     * If a value is present, invoke the specified consumer with the value,
      * otherwise do nothing.
      *
      * @param consumer block to be executed if a value is present
@@ -136,6 +150,89 @@ public final class Optional<T> {
             consumer.accept(value);
     }
 
+    /**
+     * If a value is present, and the value matches the given predicate,
+     * return an {@code Optional} describing the value, otherwise return an
+     * empty {@code Optional}.
+     *
+     * @param predicate a predicate to apply to the value, if present
+     * @return an {@code Optional} describing the value of this {@code Optional}
+     * if a value is present and the value matches the given predicate,
+     * otherwise an empty {@code Optional}
+     * @throws NullPointerException if the predicate is null
+     */
+    public Optional<T> filter(Predicate<? super T> predicate) {
+        Objects.requireNonNull(predicate);
+        if (!isPresent())
+            return this;
+        else
+            return predicate.test(value) ? this : empty();
+    }
+
+    /**
+     * If a value is present, apply the provided mapping function to it,
+     * and if the result is non-null, return an {@code Optional} describing the
+     * result.  Otherwise return an empty {@code Optional}.
+     *
+     * @apiNote This method supports post-processing on optional values, without
+     * the need to explicitly check for a return status.  For example, the
+     * following code traverses a stream of file names, selects one that has
+     * not yet been processed, and then opens that file, returning an
+     * {@code Optional<FileInputStream>}:
+     *
+     * <pre>{@code
+     *     Optional<FileInputStream> fis =
+     *         names.stream().filter(name -> !isProcessedYet(name))
+     *                       .findFirst()
+     *                       .map(name -> new FileInputStream(name));
+     * }</pre>
+     *
+     * Here, {@code findFirst} returns an {@code Optional<String>}, and then
+     * {@code map} returns an {@code Optional<FileInputStream>} for the desired
+     * file if one exists.
+     *
+     * @param <U> The type of the result of the mapping function
+     * @param mapper a mapping function to apply to the value, if present
+     * @return an {@code Optional} describing the result of applying a mapping
+     * function to the value of this {@code Optional}, if a value is present,
+     * otherwise an empty {@code Optional}
+     * @throws NullPointerException if the mapping function is null
+     */
+    public<U> Optional<U> map(Function<? super T, ? extends U> mapper) {
+        Objects.requireNonNull(mapper);
+        if (!isPresent())
+            return empty();
+        else {
+            return Optional.ofNullable(mapper.apply(value));
+        }
+    }
+
+    /**
+     * If a value is present, apply the provided {@code Optional}-bearing
+     * mapping function to it, return that result, otherwise return an empty
+     * {@code Optional}.  This method is similar to {@link #map(Function)},
+     * but the provided mapper is one whose result is already an {@code Optional},
+     * and if invoked, {@code flatMap} does not wrap it with an additional
+     * {@code Optional}.
+     *
+     * @param <U> The type parameter to the {@code Optional} returned by
+     * @param mapper a mapping function to apply to the value, if present
+     *           the mapping function
+     * @return the result of applying an {@code Optional}-bearing mapping
+     * function to the value of this {@code Optional}, if a value is present,
+     * otherwise an empty {@code Optional}
+     * @throws NullPointerException if the mapping function is null or returns
+     * a null result
+     */
+    public<U> Optional<U> flatMap(Function<? super T, Optional<U>> mapper) {
+        Objects.requireNonNull(mapper);
+        if (!isPresent())
+            return empty();
+        else {
+            return Objects.requireNonNull(mapper.apply(value));
+        }
+    }
+
     /**
      * Return the value if present, otherwise return {@code other}.
      *
diff --git a/src/share/classes/java/util/OptionalDouble.java b/src/share/classes/java/util/OptionalDouble.java
index 118a4b8d0170ebccf277a9faf5bb6f0dfab8b119..eda306cf7d422500469723125a329a0f2348a538 100644
--- a/src/share/classes/java/util/OptionalDouble.java
+++ b/src/share/classes/java/util/OptionalDouble.java
@@ -186,10 +186,10 @@ public final class OptionalDouble {
     }
 
     /**
-     * Indicates whether some other object is "equal to" this Optional. The
+     * Indicates whether some other object is "equal to" this OptionalDouble. The
      * other object is considered equal if:
      * <ul>
-     * <li>it is also an {@code OptionalInt} and;
+     * <li>it is also an {@code OptionalDouble} and;
      * <li>both instances have no value present or;
      * <li>the present values are "equal to" each other via {@code Double.compare() == 0}.
      * </ul>
@@ -226,12 +226,14 @@ public final class OptionalDouble {
     }
 
     /**
-     * Returns a non-empty string representation of this OptionalDouble suitable for
+     * {@inheritDoc}
+     *
+     * Returns a non-empty string representation of this object suitable for
      * debugging. The exact presentation format is unspecified and may vary
      * between implementations and versions.
      *
      * @implSpec If a value is present the result must include its string
-     * representation in the result. Empty and present OptionalDoubless must be
+     * representation in the result. Empty and present instances must be
      * unambiguously differentiable.
      *
      * @return the string representation of this instance
diff --git a/src/share/classes/java/util/OptionalInt.java b/src/share/classes/java/util/OptionalInt.java
index 755c2870b738adce40e4bf1b57ad976a2c308825..66478ce47138c04917e21618c45fe90d27d047dd 100644
--- a/src/share/classes/java/util/OptionalInt.java
+++ b/src/share/classes/java/util/OptionalInt.java
@@ -186,7 +186,7 @@ public final class OptionalInt {
     }
 
     /**
-     * Indicates whether some other object is "equal to" this Optional. The
+     * Indicates whether some other object is "equal to" this OptionalInt. The
      * other object is considered equal if:
      * <ul>
      * <li>it is also an {@code OptionalInt} and;
@@ -226,12 +226,14 @@ public final class OptionalInt {
     }
 
     /**
-     * Returns a non-empty string representation of this OptionalInt suitable for
+     * {@inheritDoc}
+     *
+     * Returns a non-empty string representation of this object suitable for
      * debugging. The exact presentation format is unspecified and may vary
      * between implementations and versions.
      *
      * @implSpec If a value is present the result must include its string
-     * representation in the result. Empty and present OptionalInts must be
+     * representation in the result. Empty and present instances must be
      * unambiguously differentiable.
      *
      * @return the string representation of this instance
diff --git a/src/share/classes/java/util/OptionalLong.java b/src/share/classes/java/util/OptionalLong.java
index fbb1661cc250aa24e66f28305488460025e55ffd..f07cc0d3d3a82b3648e5e0882489fb64642354b4 100644
--- a/src/share/classes/java/util/OptionalLong.java
+++ b/src/share/classes/java/util/OptionalLong.java
@@ -186,10 +186,10 @@ public final class OptionalLong {
     }
 
     /**
-     * Indicates whether some other object is "equal to" this Optional. The
+     * Indicates whether some other object is "equal to" this OptionalLong. The
      * other object is considered equal if:
      * <ul>
-     * <li>it is also an {@code OptionalInt} and;
+     * <li>it is also an {@code OptionalLong} and;
      * <li>both instances have no value present or;
      * <li>the present values are "equal to" each other via {@code ==}.
      * </ul>
@@ -226,12 +226,14 @@ public final class OptionalLong {
     }
 
     /**
-     * Returns a non-empty string representation of this OptionalLong suitable for
+     * {@inheritDoc}
+     *
+     * Returns a non-empty string representation of this object suitable for
      * debugging. The exact presentation format is unspecified and may vary
      * between implementations and versions.
      *
      * @implSpec If a value is present the result must include its string
-     * representation in the result. Empty and present OptionalLongs must be
+     * representation in the result. Empty and present instances must be
      * unambiguously differentiable.
      *
      * @return the string representation of this instance
diff --git a/src/share/classes/java/util/stream/DoubleStream.java b/src/share/classes/java/util/stream/DoubleStream.java
index 55d244fc4c31c9809b5ee854fa3df641c6066418..1b058abdf8bf943aa670feb9cef673e77bdcf92c 100644
--- a/src/share/classes/java/util/stream/DoubleStream.java
+++ b/src/share/classes/java/util/stream/DoubleStream.java
@@ -746,4 +746,26 @@ public interface DoubleStream extends BaseStream<Double, DoubleStream> {
         return StreamSupport.doubleStream(
                 new StreamSpliterators.InfiniteSupplyingSpliterator.OfDouble(Long.MAX_VALUE, s));
     }
+
+    /**
+     * Creates a lazy concatenated {@code DoubleStream} whose elements are all the
+     * elements of a first {@code DoubleStream} succeeded by all the elements of the
+     * second {@code DoubleStream}. The resulting stream is ordered if both
+     * of the input streams are ordered, and parallel if either of the input
+     * streams is parallel.
+     *
+     * @param a the first stream
+     * @param b the second stream to concatenate on to end of the first stream
+     * @return the concatenation of the two streams
+     */
+    public static DoubleStream concat(DoubleStream a, DoubleStream b) {
+        Objects.requireNonNull(a);
+        Objects.requireNonNull(b);
+
+        Spliterator.OfDouble split = new Streams.ConcatSpliterator.OfDouble(
+                a.spliterator(), b.spliterator());
+        return (a.isParallel() || b.isParallel())
+               ? StreamSupport.doubleParallelStream(split)
+               : StreamSupport.doubleStream(split);
+    }
 }
diff --git a/src/share/classes/java/util/stream/IntStream.java b/src/share/classes/java/util/stream/IntStream.java
index 3eb4409c4e590653b765f36f83bd02e138cf866a..39e0713f1cff1e864707cab177b2027be05ef4f6 100644
--- a/src/share/classes/java/util/stream/IntStream.java
+++ b/src/share/classes/java/util/stream/IntStream.java
@@ -800,4 +800,26 @@ public interface IntStream extends BaseStream<Integer, IntStream> {
                     new Streams.RangeIntSpliterator(startInclusive, endInclusive, true));
         }
     }
+
+    /**
+     * Creates a lazy concatenated {@code IntStream} whose elements are all the
+     * elements of a first {@code IntStream} succeeded by all the elements of the
+     * second {@code IntStream}. The resulting stream is ordered if both
+     * of the input streams are ordered, and parallel if either of the input
+     * streams is parallel.
+     *
+     * @param a the first stream
+     * @param b the second stream to concatenate on to end of the first stream
+     * @return the concatenation of the two streams
+     */
+    public static IntStream concat(IntStream a, IntStream b) {
+        Objects.requireNonNull(a);
+        Objects.requireNonNull(b);
+
+        Spliterator.OfInt split = new Streams.ConcatSpliterator.OfInt(
+                a.spliterator(), b.spliterator());
+        return (a.isParallel() || b.isParallel())
+               ? StreamSupport.intParallelStream(split)
+               : StreamSupport.intStream(split);
+    }
 }
diff --git a/src/share/classes/java/util/stream/LongStream.java b/src/share/classes/java/util/stream/LongStream.java
index 3bc0f76a49461ee4c610c5d98141c6248845ea76..6e3bc688923ccee3ea7333b2b6e28d6cb6424b6b 100644
--- a/src/share/classes/java/util/stream/LongStream.java
+++ b/src/share/classes/java/util/stream/LongStream.java
@@ -765,10 +765,8 @@ public interface LongStream extends BaseStream<Long, LongStream> {
             // Split the range in two and concatenate
             // Note: if the range is [Long.MIN_VALUE, Long.MAX_VALUE) then
             // the lower range, [Long.MIN_VALUE, 0) will be further split in two
-//            long m = startInclusive + Long.divideUnsigned(endExclusive - startInclusive, 2) + 1;
-//            return Streams.concat(range(startInclusive, m), range(m, endExclusive));
-            // This is temporary until Streams.concat is supported
-            throw new UnsupportedOperationException();
+            long m = startInclusive + Long.divideUnsigned(endExclusive - startInclusive, 2) + 1;
+            return concat(range(startInclusive, m), range(m, endExclusive));
         } else {
             return StreamSupport.longStream(
                     new Streams.RangeLongSpliterator(startInclusive, endExclusive, false));
@@ -801,13 +799,33 @@ public interface LongStream extends BaseStream<Long, LongStream> {
             // Note: if the range is [Long.MIN_VALUE, Long.MAX_VALUE] then
             // the lower range, [Long.MIN_VALUE, 0), and upper range,
             // [0, Long.MAX_VALUE], will both be further split in two
-//            long m = startInclusive + Long.divideUnsigned(endInclusive - startInclusive, 2) + 1;
-//            return Streams.concat(range(startInclusive, m), rangeClosed(m, endInclusive));
-            // This is temporary until Streams.concat is supported
-            throw new UnsupportedOperationException();
+            long m = startInclusive + Long.divideUnsigned(endInclusive - startInclusive, 2) + 1;
+            return concat(range(startInclusive, m), rangeClosed(m, endInclusive));
         } else {
             return StreamSupport.longStream(
                     new Streams.RangeLongSpliterator(startInclusive, endInclusive, true));
         }
     }
+
+    /**
+     * Creates a lazy concatenated {@code LongStream} whose elements are all the
+     * elements of a first {@code LongStream} succeeded by all the elements of the
+     * second {@code LongStream}. The resulting stream is ordered if both
+     * of the input streams are ordered, and parallel if either of the input
+     * streams is parallel.
+     *
+     * @param a the first stream
+     * @param b the second stream to concatenate on to end of the first stream
+     * @return the concatenation of the two streams
+     */
+    public static LongStream concat(LongStream a, LongStream b) {
+        Objects.requireNonNull(a);
+        Objects.requireNonNull(b);
+
+        Spliterator.OfLong split = new Streams.ConcatSpliterator.OfLong(
+                a.spliterator(), b.spliterator());
+        return (a.isParallel() || b.isParallel())
+               ? StreamSupport.longParallelStream(split)
+               : StreamSupport.longStream(split);
+    }
 }
diff --git a/src/share/classes/java/util/stream/Stream.java b/src/share/classes/java/util/stream/Stream.java
index 32b3585fdbff08b161e39601169e43cb0c483a60..78264e407ec1e23c480d5be83c365c64ef4f015b 100644
--- a/src/share/classes/java/util/stream/Stream.java
+++ b/src/share/classes/java/util/stream/Stream.java
@@ -883,4 +883,29 @@ public interface Stream<T> extends BaseStream<T, Stream<T>> {
         return StreamSupport.stream(
                 new StreamSpliterators.InfiniteSupplyingSpliterator.OfRef<>(Long.MAX_VALUE, s));
     }
+
+    /**
+     * Creates a lazy concatenated {@code Stream} whose elements are all the
+     * elements of a first {@code Stream} succeeded by all the elements of the
+     * second {@code Stream}. The resulting stream is ordered if both
+     * of the input streams are ordered, and parallel if either of the input
+     * streams is parallel.
+     *
+     * @param <T> The type of stream elements
+     * @param a the first stream
+     * @param b the second stream to concatenate on to end of the first
+     *        stream
+     * @return the concatenation of the two input streams
+     */
+    public static <T> Stream<T> concat(Stream<? extends T> a, Stream<? extends T> b) {
+        Objects.requireNonNull(a);
+        Objects.requireNonNull(b);
+
+        @SuppressWarnings("unchecked")
+        Spliterator<T> split = new Streams.ConcatSpliterator.OfRef<>(
+                (Spliterator<T>) a.spliterator(), (Spliterator<T>) b.spliterator());
+        return (a.isParallel() || b.isParallel())
+               ? StreamSupport.parallelStream(split)
+               : StreamSupport.stream(split);
+    }
 }
diff --git a/src/share/classes/java/util/stream/Streams.java b/src/share/classes/java/util/stream/Streams.java
index 11dbbe3d7caed7397914eaf32741d39458335538..1d49997fe22f94507c85363469a2393d5b72acaa 100644
--- a/src/share/classes/java/util/stream/Streams.java
+++ b/src/share/classes/java/util/stream/Streams.java
@@ -43,7 +43,7 @@ import java.util.function.LongConsumer;
  *
  * @since 1.8
  */
-class Streams {
+final class Streams {
 
     private Streams() {
         throw new Error("no instances");
@@ -670,4 +670,147 @@ class Streams {
             }
         }
     }
+
+    abstract static class ConcatSpliterator<T, T_SPLITR extends Spliterator<T>>
+            implements Spliterator<T> {
+        protected final T_SPLITR aSpliterator;
+        protected final T_SPLITR bSpliterator;
+        // True when no split has occurred, otherwise false
+        boolean beforeSplit;
+        // Never read after splitting
+        final boolean unsized;
+
+        public ConcatSpliterator(T_SPLITR aSpliterator, T_SPLITR bSpliterator) {
+            this.aSpliterator = aSpliterator;
+            this.bSpliterator = bSpliterator;
+            beforeSplit = true;
+            // The spliterator is unsized before splitting if a and b are
+            // sized and the sum of the estimates overflows
+            unsized = aSpliterator.hasCharacteristics(SIZED)
+                      && aSpliterator.hasCharacteristics(SIZED)
+                      && aSpliterator.estimateSize() + bSpliterator.estimateSize() < 0;
+        }
+
+        @Override
+        public T_SPLITR trySplit() {
+            T_SPLITR ret = beforeSplit ? aSpliterator : (T_SPLITR) bSpliterator.trySplit();
+            beforeSplit = false;
+            return ret;
+        }
+
+        @Override
+        public boolean tryAdvance(Consumer<? super T> consumer) {
+            boolean hasNext;
+            if (beforeSplit) {
+                hasNext = aSpliterator.tryAdvance(consumer);
+                if (!hasNext) {
+                    beforeSplit = false;
+                    hasNext = bSpliterator.tryAdvance(consumer);
+                }
+            }
+            else
+                hasNext = bSpliterator.tryAdvance(consumer);
+            return hasNext;
+        }
+
+        @Override
+        public void forEachRemaining(Consumer<? super T> consumer) {
+            if (beforeSplit)
+                aSpliterator.forEachRemaining(consumer);
+            bSpliterator.forEachRemaining(consumer);
+        }
+
+        @Override
+        public long estimateSize() {
+            if (beforeSplit) {
+                // If one or both estimates are Long.MAX_VALUE then the sum
+                // will either be Long.MAX_VALUE or overflow to a negative value
+                long size = aSpliterator.estimateSize() + bSpliterator.estimateSize();
+                return (size >= 0) ? size : Long.MAX_VALUE;
+            }
+            else {
+                return bSpliterator.estimateSize();
+            }
+        }
+
+        @Override
+        public int characteristics() {
+            if (beforeSplit) {
+                // Concatenation loses DISTINCT and SORTED characteristics
+                return aSpliterator.characteristics() & bSpliterator.characteristics()
+                       & ~(Spliterator.DISTINCT | Spliterator.SORTED
+                           | (unsized ? Spliterator.SIZED | Spliterator.SUBSIZED : 0));
+            }
+            else {
+                return bSpliterator.characteristics();
+            }
+        }
+
+        @Override
+        public Comparator<? super T> getComparator() {
+            if (beforeSplit)
+                throw new IllegalStateException();
+            return bSpliterator.getComparator();
+        }
+
+        static class OfRef<T> extends ConcatSpliterator<T, Spliterator<T>> {
+            OfRef(Spliterator<T> aSpliterator, Spliterator<T> bSpliterator) {
+                super(aSpliterator, bSpliterator);
+            }
+        }
+
+        private static abstract class OfPrimitive<T, T_CONS, T_SPLITR extends Spliterator.OfPrimitive<T, T_CONS, T_SPLITR>>
+                extends ConcatSpliterator<T, T_SPLITR>
+                implements Spliterator.OfPrimitive<T, T_CONS, T_SPLITR> {
+            private OfPrimitive(T_SPLITR aSpliterator, T_SPLITR bSpliterator) {
+                super(aSpliterator, bSpliterator);
+            }
+
+            @Override
+            public boolean tryAdvance(T_CONS action) {
+                boolean hasNext;
+                if (beforeSplit) {
+                    hasNext = aSpliterator.tryAdvance(action);
+                    if (!hasNext) {
+                        beforeSplit = false;
+                        hasNext = bSpliterator.tryAdvance(action);
+                    }
+                }
+                else
+                    hasNext = bSpliterator.tryAdvance(action);
+                return hasNext;
+            }
+
+            @Override
+            public void forEachRemaining(T_CONS action) {
+                if (beforeSplit)
+                    aSpliterator.forEachRemaining(action);
+                bSpliterator.forEachRemaining(action);
+            }
+        }
+
+        static class OfInt
+                extends ConcatSpliterator.OfPrimitive<Integer, IntConsumer, Spliterator.OfInt>
+                implements Spliterator.OfInt {
+            OfInt(Spliterator.OfInt aSpliterator, Spliterator.OfInt bSpliterator) {
+                super(aSpliterator, bSpliterator);
+            }
+        }
+
+        static class OfLong
+                extends ConcatSpliterator.OfPrimitive<Long, LongConsumer, Spliterator.OfLong>
+                implements Spliterator.OfLong {
+            OfLong(Spliterator.OfLong aSpliterator, Spliterator.OfLong bSpliterator) {
+                super(aSpliterator, bSpliterator);
+            }
+        }
+
+        static class OfDouble
+                extends ConcatSpliterator.OfPrimitive<Double, DoubleConsumer, Spliterator.OfDouble>
+                implements Spliterator.OfDouble {
+            OfDouble(Spliterator.OfDouble aSpliterator, Spliterator.OfDouble bSpliterator) {
+                super(aSpliterator, bSpliterator);
+            }
+        }
+    }
 }
diff --git a/test/java/util/Collection/MOAT.java b/test/java/util/Collection/MOAT.java
index 7abc669d4b91d9e1b80f8206b99cd00b98464b26..a5b2c42e47b757d6704b124c53b2c8a447580804 100644
--- a/test/java/util/Collection/MOAT.java
+++ b/test/java/util/Collection/MOAT.java
@@ -71,6 +71,14 @@ public class MOAT {
         testCollection(new LinkedList<Integer>());
         testCollection(new LinkedList<Integer>().subList(0,0));
         testCollection(new TreeSet<Integer>());
+        testCollection(Collections.checkedList(new ArrayList<Integer>(), Integer.class));
+        testCollection(Collections.synchronizedList(new ArrayList<Integer>()));
+        testCollection(Collections.checkedSet(new HashSet<Integer>(), Integer.class));
+        testCollection(Collections.checkedSortedSet(new TreeSet<Integer>(), Integer.class));
+        testCollection(Collections.checkedNavigableSet(new TreeSet<Integer>(), Integer.class));
+        testCollection(Collections.synchronizedSet(new HashSet<Integer>()));
+        testCollection(Collections.synchronizedSortedSet(new TreeSet<Integer>()));
+        testCollection(Collections.synchronizedNavigableSet(new TreeSet<Integer>()));
 
         testCollection(new CopyOnWriteArrayList<Integer>());
         testCollection(new CopyOnWriteArrayList<Integer>().subList(0,0));
@@ -98,6 +106,12 @@ public class MOAT {
         testMap(new Hashtable<Integer,Integer>());
         testMap(new ConcurrentHashMap<Integer,Integer>(10, 0.5f));
         testMap(new ConcurrentSkipListMap<Integer,Integer>());
+        testMap(Collections.checkedMap(new HashMap<Integer,Integer>(), Integer.class, Integer.class));
+        testMap(Collections.checkedSortedMap(new TreeMap<Integer,Integer>(), Integer.class, Integer.class));
+        testMap(Collections.checkedNavigableMap(new TreeMap<Integer,Integer>(), Integer.class, Integer.class));
+        testMap(Collections.synchronizedMap(new HashMap<Integer,Integer>()));
+        testMap(Collections.synchronizedSortedMap(new TreeMap<Integer,Integer>()));
+        testMap(Collections.synchronizedNavigableMap(new TreeMap<Integer,Integer>()));
 
         // Empty collections
         final List<Integer> emptyArray = Arrays.asList(new Integer[]{});
@@ -117,19 +131,29 @@ public class MOAT {
         testCollection(emptySet);
         testEmptySet(emptySet);
         testEmptySet(EMPTY_SET);
+        testEmptySet(Collections.emptySet());
+        testEmptySet(Collections.emptySortedSet());
+        testEmptySet(Collections.emptyNavigableSet());
         testImmutableSet(emptySet);
 
         List<Integer> emptyList = emptyList();
         testCollection(emptyList);
         testEmptyList(emptyList);
         testEmptyList(EMPTY_LIST);
+        testEmptyList(Collections.emptyList());
         testImmutableList(emptyList);
 
         Map<Integer,Integer> emptyMap = emptyMap();
         testMap(emptyMap);
         testEmptyMap(emptyMap);
         testEmptyMap(EMPTY_MAP);
+        testEmptyMap(Collections.emptyMap());
+        testEmptyMap(Collections.emptySortedMap());
+        testEmptyMap(Collections.emptyNavigableMap());
         testImmutableMap(emptyMap);
+        testImmutableMap(Collections.emptyMap());
+        testImmutableMap(Collections.emptySortedMap());
+        testImmutableMap(Collections.emptyNavigableMap());
 
         // Singleton collections
         Set<Integer> singletonSet = singleton(1);
diff --git a/test/java/util/Collections/CheckedIdentityMap.java b/test/java/util/Collections/CheckedIdentityMap.java
index befbd23b81a238f3202a50ddc80359f1c93aa79e..4c2e9d2bf5e7d1ecc8e2eb4557cdd294b9c05017 100644
--- a/test/java/util/Collections/CheckedIdentityMap.java
+++ b/test/java/util/Collections/CheckedIdentityMap.java
@@ -24,59 +24,42 @@
 /*
  * @test
  * @bug 6585904
+ * @run testng CheckedIdentityMap
  * @summary Checked collections with underlying maps with identity comparisons
  */
 
 import java.util.*;
 import static java.util.Collections.*;
 
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNotEquals;
+
+import org.testng.annotations.Test;
+
 public class CheckedIdentityMap {
-    void test(String[] args) throws Throwable {
+
+    @Test
+    public void testHashCode() {
         Map<Integer, Integer> m1 = checkedMap(
             new IdentityHashMap<Integer, Integer>(),
             Integer.class, Integer.class);
         Map<Integer, Integer> m2 = checkedMap(
             new IdentityHashMap<Integer, Integer>(),
             Integer.class, Integer.class);
+        // NB: these are unique instances. Compare vs. Integer.valueOf(1)
         m1.put(new Integer(1), new Integer(1));
         m2.put(new Integer(1), new Integer(1));
 
         Map.Entry<Integer, Integer> e1 = m1.entrySet().iterator().next();
         Map.Entry<Integer, Integer> e2 = m2.entrySet().iterator().next();
-        check(! e1.equals(e2));
-        check(e1.hashCode() == hashCode(e1));
-        check(e2.hashCode() == hashCode(e2));
+
+        assertNotEquals(e1, e2);
+        assertEquals(e1.hashCode(), hashCode(e1));
+        assertEquals(e2.hashCode(), hashCode(e2));
     }
 
-    int hashCode(Map.Entry<?,?> e) {
+    static int hashCode(Map.Entry<?,?> e) {
         return (System.identityHashCode(e.getKey()) ^
                 System.identityHashCode(e.getValue()));
     }
-
-    //--------------------- Infrastructure ---------------------------
-    volatile int passed = 0, failed = 0;
-    void pass() {passed++;}
-    void fail() {failed++; Thread.dumpStack();}
-    void fail(String msg) {System.err.println(msg); fail();}
-    void unexpected(Throwable t) {failed++; t.printStackTrace();}
-    void check(boolean cond) {if (cond) pass(); else fail();}
-    void equal(Object x, Object y) {
-        if (x == null ? y == null : x.equals(y)) pass();
-        else fail(x + " not equal to " + y);}
-    public static void main(String[] args) throws Throwable {
-        new CheckedIdentityMap().instanceMain(args);}
-    void instanceMain(String[] args) throws Throwable {
-        try {test(args);} catch (Throwable t) {unexpected(t);}
-        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
-        if (failed > 0) throw new AssertionError("Some tests failed");}
-    abstract class F {abstract void f() throws Throwable;}
-    void THROWS(Class<? extends Throwable> k, F... fs) {
-        for (F f : fs)
-            try {f.f(); fail("Expected " + k.getName() + " not thrown");}
-            catch (Throwable t) {
-                if (k.isAssignableFrom(t.getClass())) pass();
-                else unexpected(t);}}
-    Thread checkedThread(final Runnable r) {
-        return new Thread() {public void run() {
-            try {r.run();} catch (Throwable t) {unexpected(t);}}};}
 }
diff --git a/test/java/util/Collections/CheckedMapBash.java b/test/java/util/Collections/CheckedMapBash.java
index 61c7dd09cfe2472fead2d39c904eb49679f0b6e8..880d35b56463332f6ca609db2ea9598036676412 100644
--- a/test/java/util/Collections/CheckedMapBash.java
+++ b/test/java/util/Collections/CheckedMapBash.java
@@ -23,76 +23,83 @@
 
 /*
  * @test
- * @bug     4904067 5023830
+ * @bug     4904067 5023830 7129185
  * @summary Unit test for Collections.checkedMap
  * @author  Josh Bloch
+ * @run testng CheckedMapBash
  */
 
 import java.util.*;
+import java.util.function.Supplier;
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertTrue;
 
 public class CheckedMapBash {
-    static Random rnd = new Random();
-    static Object nil = new Integer(0);
-
-    public static void main(String[] args) {
-        int numItr = 100;
-        int mapSize = 100;
-
-        // Linked List test
-        for (int i=0; i<numItr; i++) {
-            Map m = newMap();
-            Object head = nil;
-
-            for (int j=0; j<mapSize; j++) {
-                Object newHead;
-                do {
-                    newHead = new Integer(rnd.nextInt());
-                } while (m.containsKey(newHead));
-                m.put(newHead, head);
-                head = newHead;
-            }
-            if (m.size() != mapSize)
-                fail("Size not as expected.");
-
-            {
-                HashMap hm = new HashMap(m);
-                if (! (hm.hashCode() == m.hashCode() &&
-                       hm.entrySet().hashCode() == m.entrySet().hashCode() &&
-                       hm.keySet().hashCode() == m.keySet().hashCode()))
-                    fail("Incorrect hashCode computation.");
-
-                if (! (hm.equals(m) &&
-                       hm.entrySet().equals(m.entrySet()) &&
-                       hm.keySet().equals(m.keySet()) &&
-                       m.equals(hm) &&
-                       m.entrySet().equals(hm.entrySet()) &&
-                       m.keySet().equals(hm.keySet())))
-                    fail("Incorrect equals computation.");
-            }
-
-            Map m2 = newMap(); m2.putAll(m);
-            m2.values().removeAll(m.keySet());
-            if (m2.size()!= 1 || !m2.containsValue(nil))
-                fail("Collection views test failed.");
-
-            int j=0;
-            while (head != nil) {
-                if (!m.containsKey(head))
-                    fail("Linked list doesn't contain a link.");
-                Object newHead = m.get(head);
-                if (newHead == null)
-                    fail("Could not retrieve a link.");
-                m.remove(head);
-                head = newHead;
-                j++;
-            }
-            if (!m.isEmpty())
-                fail("Map nonempty after removing all links.");
-            if (j != mapSize)
-                fail("Linked list size not as expected.");
+    static final Random rnd = new Random();
+    static final Object nil = new Integer(0);
+    static final int numItr = 100;
+    static final int mapSize = 100;
+
+    @Test(dataProvider = "Bash.Supplier<Map<Integer,Integer>>")
+    public static void testCheckedMap(String description, Supplier<Map<Integer,Integer>> supplier) {
+        Map m = supplier.get();
+        Object head = nil;
+
+        for (int j=0; j<mapSize; j++) {
+            Object newHead;
+            do {
+                newHead = new Integer(rnd.nextInt());
+            } while (m.containsKey(newHead));
+            m.put(newHead, head);
+            head = newHead;
+        }
+        if (m.size() != mapSize)
+            fail("Size not as expected.");
+
+        {
+            HashMap hm = new HashMap(m);
+            if (! (hm.hashCode() == m.hashCode() &&
+                   hm.entrySet().hashCode() == m.entrySet().hashCode() &&
+                   hm.keySet().hashCode() == m.keySet().hashCode()))
+                fail("Incorrect hashCode computation.");
+
+            if (! (hm.equals(m) &&
+                   hm.entrySet().equals(m.entrySet()) &&
+                   hm.keySet().equals(m.keySet()) &&
+                   m.equals(hm) &&
+                   m.entrySet().equals(hm.entrySet()) &&
+                   m.keySet().equals(hm.keySet())))
+                fail("Incorrect equals computation.");
         }
 
-        Map m = newMap();
+        Map m2 = supplier.get(); m2.putAll(m);
+        m2.values().removeAll(m.keySet());
+        if (m2.size()!= 1 || !m2.containsValue(nil))
+            fail("Collection views test failed.");
+
+        int j=0;
+        while (head != nil) {
+            if (!m.containsKey(head))
+                fail("Linked list doesn't contain a link.");
+            Object newHead = m.get(head);
+            if (newHead == null)
+                fail("Could not retrieve a link.");
+            m.remove(head);
+            head = newHead;
+            j++;
+        }
+        if (!m.isEmpty())
+            fail("Map nonempty after removing all links.");
+        if (j != mapSize)
+            fail("Linked list size not as expected.");
+    }
+
+    @Test(dataProvider = "Supplier<Map<Integer,Integer>>")
+    public static void testCheckeMap2(String description, Supplier<Map<Integer,Integer>> supplier) {
+        Map m = supplier.get();
         for (int i=0; i<mapSize; i++)
             if (m.put(new Integer(i), new Integer(2*i)) != null)
                 fail("put returns a non-null value erroenously.");
@@ -101,7 +108,7 @@ public class CheckedMapBash {
                 fail("contains value "+i);
         if (m.put(nil, nil) == null)
             fail("put returns a null value erroenously.");
-        Map m2 = newMap(); m2.putAll(m);
+        Map m2 = supplier.get(); m2.putAll(m);
         if (!m.equals(m2))
             fail("Clone not equal to original. (1)");
         if (!m2.equals(m))
@@ -134,16 +141,36 @@ public class CheckedMapBash {
             fail("Iterator.remove() failed");
     }
 
-    static Map newMap() {
-        Map m = Collections.checkedMap(new HashMap(),
-                                       Integer.class, Integer.class);
 
-        if (!m.isEmpty())
-            fail("New instance non empty.");
-        return m;
+    @DataProvider(name = "Bash.Supplier<Map<Integer,Integer>>", parallel = true)
+    public static Iterator<Object[]> bashNavigableMapProvider() {
+        ArrayList<Object[]> iters = new ArrayList<>(makeCheckedMaps());
+        iters.ensureCapacity(numItr * iters.size());
+        for(int each=1; each < numItr; each++) {
+            iters.addAll( makeCheckedMaps());
+        }
+        return iters.iterator();
+    }
+
+    @DataProvider(name = "Supplier<Map<Integer,Integer>>", parallel = true)
+    public static Iterator<Object[]> navigableMapProvider() {
+        return makeCheckedMaps().iterator();
     }
 
-    static void fail(String s) {
-        throw new RuntimeException(s);
+    public static Collection<Object[]> makeCheckedMaps() {
+        return Arrays.asList(
+            new Object[]{"Collections.checkedMap(HashMap)",
+                (Supplier) () -> {return Collections.checkedMap(new HashMap(), Integer.class, Integer.class);}},
+            new Object[]{"Collections.checkedMap(TreeSet(reverseOrder)",
+                (Supplier) () -> {return Collections.checkedMap(new TreeMap(Collections.reverseOrder()), Integer.class, Integer.class);}},
+            new Object[]{"Collections.checkedMap(TreeSet).descendingSet()",
+                (Supplier) () -> {return Collections.checkedMap(new TreeMap().descendingMap(), Integer.class, Integer.class);}},
+            new Object[]{"Collections.checkedNavigableMap(TreeSet)",
+                (Supplier) () -> {return Collections.checkedNavigableMap(new TreeMap(), Integer.class, Integer.class);}},
+            new Object[]{"Collections.checkedNavigableMap(TreeSet(reverseOrder)",
+                (Supplier) () -> {return Collections.checkedNavigableMap(new TreeMap(Collections.reverseOrder()), Integer.class, Integer.class);}},
+            new Object[]{"Collections.checkedNavigableMap().descendingSet()",
+                (Supplier) () -> {return Collections.checkedNavigableMap(new TreeMap().descendingMap(), Integer.class, Integer.class);}}
+            );
     }
 }
diff --git a/test/java/util/Collections/CheckedSetBash.java b/test/java/util/Collections/CheckedSetBash.java
index 714fcae896a822f7ab822fd96ef8cad7aebf4c52..0d87cb1595350d8a4046acc89ca85173a13eba65 100644
--- a/test/java/util/Collections/CheckedSetBash.java
+++ b/test/java/util/Collections/CheckedSetBash.java
@@ -23,82 +23,93 @@
 
 /*
  * @test
- * @bug     4904067
+ * @bug     4904067 7129185
  * @summary Unit test for Collections.checkedSet
  * @author  Josh Bloch
+ * @run testng CheckedSetBash
  */
 
 import java.util.*;
+import java.util.function.Supplier;
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertTrue;
 
 public class CheckedSetBash {
-    static Random rnd = new Random();
-
-    public static void main(String[] args) {
-        int numItr = 100;
-        int setSize = 100;
-
-        for (int i=0; i<numItr; i++) {
-            Set s1 = newSet();
-            AddRandoms(s1, setSize);
-
-            Set s2 = newSet();
-            AddRandoms(s2, setSize);
-
-            Set intersection = clone(s1);
-            intersection.retainAll(s2);
-            Set diff1 = clone(s1); diff1.removeAll(s2);
-            Set diff2 = clone(s2); diff2.removeAll(s1);
-            Set union = clone(s1); union.addAll(s2);
-
-            if (diff1.removeAll(diff2))
-                fail("Set algebra identity 2 failed");
-            if (diff1.removeAll(intersection))
-                fail("Set algebra identity 3 failed");
-            if (diff2.removeAll(diff1))
-                fail("Set algebra identity 4 failed");
-            if (diff2.removeAll(intersection))
-                fail("Set algebra identity 5 failed");
-            if (intersection.removeAll(diff1))
-                fail("Set algebra identity 6 failed");
-            if (intersection.removeAll(diff1))
-                fail("Set algebra identity 7 failed");
-
-            intersection.addAll(diff1); intersection.addAll(diff2);
-            if (!intersection.equals(union))
-                fail("Set algebra identity 1 failed");
-
-            if (new HashSet(union).hashCode() != union.hashCode())
-                fail("Incorrect hashCode computation.");
-
-            Iterator e = union.iterator();
-            while (e.hasNext())
-                if (!intersection.remove(e.next()))
-                    fail("Couldn't remove element from copy.");
-            if (!intersection.isEmpty())
-                fail("Copy nonempty after deleting all elements.");
-
-            e = union.iterator();
-            while (e.hasNext()) {
-                Object o = e.next();
-                if (!union.contains(o))
-                    fail("Set doesn't contain one of its elements.");
-                e.remove();
-                if (union.contains(o))
-                    fail("Set contains element after deletion.");
-            }
-            if (!union.isEmpty())
-                fail("Set nonempty after deleting all elements.");
-
-            s1.clear();
-            if (!s1.isEmpty())
-                fail("Set nonempty after clear.");
+    static final int numItr = 100;
+    static final int setSize = 100;
+    static final Random rnd = new Random();
+
+    @Test(dataProvider = "Supplier<Set<Integer>>")
+    public static void testCheckedSet(String description, Supplier<Set<Integer>> supplier) {
+
+        Set<Integer> s1 = supplier.get();
+        assertTrue(s1.isEmpty());
+
+        AddRandoms(s1, setSize);
+
+        Set<Integer> s2 = supplier.get();
+
+        assertTrue(s2.isEmpty());
+
+        AddRandoms(s2, setSize);
+
+        Set<Integer> intersection = clone(s1, supplier);
+        intersection.retainAll(s2);
+        Set<Integer> diff1 = clone(s1, supplier); diff1.removeAll(s2);
+        Set<Integer> diff2 = clone(s2, supplier); diff2.removeAll(s1);
+        Set<Integer> union = clone(s1, supplier); union.addAll(s2);
+
+        if (diff1.removeAll(diff2))
+            fail("Set algebra identity 2 failed");
+        if (diff1.removeAll(intersection))
+            fail("Set algebra identity 3 failed");
+        if (diff2.removeAll(diff1))
+            fail("Set algebra identity 4 failed");
+        if (diff2.removeAll(intersection))
+            fail("Set algebra identity 5 failed");
+        if (intersection.removeAll(diff1))
+            fail("Set algebra identity 6 failed");
+        if (intersection.removeAll(diff1))
+            fail("Set algebra identity 7 failed");
+
+        intersection.addAll(diff1); intersection.addAll(diff2);
+        if (!intersection.equals(union))
+            fail("Set algebra identity 1 failed");
+
+        if (new HashSet(union).hashCode() != union.hashCode())
+            fail("Incorrect hashCode computation.");
+
+        Iterator e = union.iterator();
+        while (e.hasNext())
+            if (!intersection.remove(e.next()))
+                fail("Couldn't remove element from copy.");
+        if (!intersection.isEmpty())
+            fail("Copy nonempty after deleting all elements.");
+
+        e = union.iterator();
+        while (e.hasNext()) {
+            Object o = e.next();
+            if (!union.contains(o))
+                fail("Set doesn't contain one of its elements.");
+            e.remove();
+            if (union.contains(o))
+                fail("Set contains element after deletion.");
         }
+        if (!union.isEmpty())
+            fail("Set nonempty after deleting all elements.");
+
+        s1.clear();
+        if (!s1.isEmpty())
+            fail("Set nonempty after clear.");
     }
 
     // Done inefficiently so as to exercise toArray
-    static Set clone(Set s) {
-        Set clone = newSet();
-        List arrayList = Arrays.asList(s.toArray());
+    static <T> Set<T> clone(Set<T> s, Supplier<Set<T>> supplier) {
+        Set<T> clone = supplier.get();
+        List<T> arrayList = Arrays.asList((T[]) s.toArray());
         clone.addAll(arrayList);
         if (!s.equals(clone))
             fail("Set not equal to copy.");
@@ -109,13 +120,6 @@ public class CheckedSetBash {
         return clone;
     }
 
-    static Set newSet() {
-        Set s = Collections.checkedSet(new HashSet(), Integer.class);
-        if (!s.isEmpty())
-            fail("New instance non empty.");
-        return s;
-    }
-
     static void AddRandoms(Set s, int n) {
         for (int i=0; i<n; i++) {
             int r = rnd.nextInt() % n;
@@ -136,8 +140,30 @@ public class CheckedSetBash {
         }
     }
 
-    static void fail(String s) {
-        throw new RuntimeException(s);
+    @DataProvider(name = "Supplier<Set<Integer>>", parallel = true)
+    public static Iterator<Object[]> navigableSetsProvider() {
+        ArrayList<Object[]> iters = new ArrayList<>(makeCheckedSets());
+        iters.ensureCapacity(numItr * iters.size());
+        for(int each=1; each < numItr; each++) {
+            iters.addAll( makeCheckedSets());
+        }
+        return iters.iterator();
+    }
 
+    public static Collection<Object[]> makeCheckedSets() {
+        return Arrays.asList(
+            new Object[]{"Collections.checkedSet(HashSet)",
+                (Supplier) () -> {return Collections.checkedSet(new HashSet(), Integer.class);}},
+            new Object[]{"Collections.checkedSet(TreeSet(reverseOrder)",
+                (Supplier) () -> {return Collections.checkedSet(new TreeSet(Collections.reverseOrder()), Integer.class);}},
+            new Object[]{"Collections.checkedSet(TreeSet).descendingSet()",
+                (Supplier) () -> {return Collections.checkedSet(new TreeSet().descendingSet(), Integer.class);}},
+            new Object[]{"Collections.checkedNavigableSet(TreeSet)",
+                (Supplier) () -> {return Collections.checkedNavigableSet(new TreeSet(), Integer.class);}},
+            new Object[]{"Collections.checkedNavigableSet(TreeSet(reverseOrder)",
+                (Supplier) () -> {return Collections.checkedNavigableSet(new TreeSet(Collections.reverseOrder()), Integer.class);}},
+            new Object[]{"Collections.checkedNavigableSet().descendingSet()",
+                (Supplier) () -> {return Collections.checkedNavigableSet(new TreeSet().descendingSet(), Integer.class);}}
+            );
     }
 }
diff --git a/test/java/util/Collections/EmptyCollectionSerialization.java b/test/java/util/Collections/EmptyCollectionSerialization.java
index 7bbe0bf14d0373c09be292df5befdd643c8867ed..1369663ffc5a07555ae75680e0f4525fb28676e8 100644
--- a/test/java/util/Collections/EmptyCollectionSerialization.java
+++ b/test/java/util/Collections/EmptyCollectionSerialization.java
@@ -23,13 +23,20 @@
 
 /*
  * @test
- * @bug     4684279
+ * @bug     4684279 7129185
  * @summary Empty utility collections should be singletons
  * @author  Josh Bloch
+ * @run testng EmptyCollectionSerialization
  */
 
 import java.util.*;
+import java.util.function.Supplier;
 import java.io.*;
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertSame;
 
 public class EmptyCollectionSerialization {
     private static Object patheticDeepCopy(Object o) throws Exception {
@@ -45,16 +52,48 @@ public class EmptyCollectionSerialization {
         return ois.readObject();
     }
 
-    private static boolean isSingleton(Object o) throws Exception {
-        return patheticDeepCopy(o) == o;
+    @Test(dataProvider="SerializableSingletons")
+    public static void serializableSingletons(String description, Supplier<Object> o) {
+        try {
+            Object singleton = o.get();
+            assertSame(o.get(), singleton, description + ": broken Supplier not returning singleton");
+            Object copy = patheticDeepCopy(singleton);
+            assertSame( copy, singleton, description + ": " +
+                copy.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(copy)) +
+                " is not the singleton " +
+                singleton.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(singleton)));
+        } catch(Exception all) {
+            fail(description + ": Unexpected Exception", all);
+        }
+    }
+
+    @DataProvider(name = "SerializableSingletons", parallel = true)
+    public static Iterator<Object[]> navigableMapProvider() {
+        return makeSingletons().iterator();
     }
 
-    public static void main(String[] args) throws Exception {
-        if (!isSingleton(Collections.EMPTY_SET))
-            throw new Exception("EMPTY_SET");
-        if (!isSingleton(Collections.EMPTY_LIST))
-            throw new Exception("EMPTY_LIST");
-        if (!isSingleton(Collections.EMPTY_MAP))
-            throw new Exception("EMPTY_MAP");
+    public static Collection<Object[]> makeSingletons() {
+        return Arrays.asList(
+            new Object[]{"Collections.EMPTY_LIST",
+                (Supplier) () -> {return Collections.EMPTY_LIST;}},
+            new Object[]{"Collections.EMPTY_MAP",
+                (Supplier) () -> {return Collections.EMPTY_MAP;}},
+            new Object[]{"Collections.EMPTY_SET",
+                (Supplier) () -> {return Collections.EMPTY_SET;}},
+            new Object[]{"Collections.singletonMap()",
+                (Supplier) () -> {return Collections.emptyList();}},
+            new Object[]{"Collections.emptyMap()",
+                (Supplier) () -> {return Collections.emptyMap();}},
+            new Object[]{"Collections.emptySet()",
+                (Supplier) () -> {return Collections.emptySet();}},
+            new Object[]{"Collections.emptySortedSet()",
+                (Supplier) () -> {return Collections.emptySortedSet();}},
+            new Object[]{"Collections.emptySortedMap()",
+                (Supplier) () -> {return Collections.emptySortedMap();}},
+            new Object[]{"Collections.emptyNavigableSet()",
+                (Supplier) () -> {return Collections.emptyNavigableSet();}},
+            new Object[]{"Collections.emptyNavigableMap()",
+                (Supplier) () -> {return Collections.emptyNavigableMap();}}
+            );
     }
 }
diff --git a/test/java/util/Collections/EmptyNavigableMap.java b/test/java/util/Collections/EmptyNavigableMap.java
new file mode 100644
index 0000000000000000000000000000000000000000..ba8e67b42a499ad139eab7c791dea3cc137c4c00
--- /dev/null
+++ b/test/java/util/Collections/EmptyNavigableMap.java
@@ -0,0 +1,373 @@
+/*
+ * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 4533691 7129185
+ * @summary Unit test for Collections.emptyNavigableMap
+ * @run testng EmptyNavigableMap
+ */
+import java.math.BigInteger;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.NavigableMap;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertSame;
+
+public class EmptyNavigableMap {
+
+    public static <T> void assertInstance(T actual, Class<? extends T> expected) {
+        assertInstance(expected.isInstance(actual), null);
+    }
+
+    public static <T> void assertInstance(T actual, Class<? extends T> expected, String message) {
+        assertTrue(expected.isInstance(actual), ((null != message) ? message : "")
+            + " " + (actual == null ? "<null>" : actual.getClass().getSimpleName()) + " != " + expected.getSimpleName() + ". ");
+    }
+
+    public static <T extends Throwable> void assertEmptyNavigableMap(Object obj) {
+        assertInstance(obj, NavigableMap.class);
+        assertTrue(((NavigableMap)obj).isEmpty() && (((NavigableMap)obj).size() == 0));
+    }
+
+    public static <T extends Throwable> void assertEmptyNavigableMap(Object obj, String message) {
+        assertInstance(obj, NavigableMap.class, message);
+        assertTrue(((NavigableMap)obj).isEmpty() && (((NavigableMap)obj).size() == 0),
+            ((null != message) ? message : "") + " Not empty. ");
+    }
+
+    public interface Thrower<T extends Throwable> {
+
+        public void run() throws T;
+    }
+
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable) {
+        assertThrows(thrower, throwable, null);
+    }
+
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable, String message) {
+        Throwable result;
+        try {
+            thrower.run();
+            fail(((null != message) ? message : "") + "Failed to throw " + throwable.getCanonicalName() + ". ");
+            return;
+        } catch (Throwable caught) {
+            result = caught;
+        }
+
+        assertInstance(result, throwable, ((null != message) ? message : "") + "Failed to throw " + throwable.getCanonicalName() + ". ");
+    }
+
+    public static final boolean isDescending(SortedMap<?,?> set) {
+        if (null == set.comparator()) {
+            // natural order
+            return false;
+        }
+
+        if (Collections.reverseOrder() == set.comparator()) {
+            // reverse natural order.
+            return true;
+        }
+
+        if (set.comparator().equals(Collections.reverseOrder(Collections.reverseOrder(set.comparator())))) {
+            // it's a Collections.reverseOrder(Comparator).
+            return true;
+        }
+
+        throw new IllegalStateException("can't determine ordering for " + set);
+    }
+
+    /**
+     * Tests that the comparator is {@code null}.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testComparatorIsNull(String description, NavigableMap<?,?> navigableMap) {
+        Comparator comparator = navigableMap.comparator();
+
+        assertTrue(comparator == null || comparator == Collections.reverseOrder(), description + ": Comparator (" + comparator + ") is not null.");
+    }
+
+    /**
+     * Tests that contains requires Comparable
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testContainsRequiresComparable(String description, NavigableMap<?,?> navigableMap) {
+        assertThrows(() -> {
+            navigableMap.containsKey(new Object());
+        },
+            ClassCastException.class,
+            description + ": Compareable should be required");
+    }
+
+    /**
+     * Tests that the contains method returns {@code false}.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testContains(String description, NavigableMap<?,?> navigableMap) {
+        assertFalse(navigableMap.containsKey(new Integer(1)),
+            description + ": Should not contain any elements.");
+        assertFalse(navigableMap.containsValue(new Integer(1)),
+            description + ": Should not contain any elements.");
+    }
+
+    /**
+     * Tests that the containsAll method returns {@code false}.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testContainsAll(String description, NavigableMap<?,?> navigableMap) {
+        TreeMap treeMap = new TreeMap();
+        treeMap.put("1", 1);
+        treeMap.put("2", 2);
+        treeMap.put("3", 3);
+
+        assertFalse(navigableMap.equals(treeMap), "Should not contain any elements.");
+    }
+
+    /**
+     * Tests that the iterator is empty.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testEmptyIterator(String description, NavigableMap<?,?> navigableMap) {
+        assertFalse(navigableMap.keySet().iterator().hasNext(), "The iterator is not empty.");
+        assertFalse(navigableMap.values().iterator().hasNext(), "The iterator is not empty.");
+        assertFalse(navigableMap.entrySet().iterator().hasNext(), "The iterator is not empty.");
+    }
+
+    /**
+     * Tests that the set is empty.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testIsEmpty(String description, NavigableMap<?,?> navigableMap) {
+        assertTrue(navigableMap.isEmpty(), "The set is not empty.");
+    }
+
+    /**
+     * Tests the headMap() method.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testHeadMap(String description, NavigableMap navigableMap) {
+        assertThrows(
+            () -> { NavigableMap ss = navigableMap.headMap(null, false); },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> { NavigableMap ss = navigableMap.headMap(new Object(), true); },
+            ClassCastException.class,
+            description + ": Must throw ClassCastException for non-Comparable element");
+
+        NavigableMap ss = navigableMap.headMap("1", false);
+
+        assertEmptyNavigableMap(ss, description + ": Returned value is not empty navigable set.");
+    }
+
+    /**
+     * Tests that the size is 0.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testSizeIsZero(String description, NavigableMap<?,?> navigableMap) {
+        assertTrue(0 == navigableMap.size(), "The size of the set is not 0.");
+    }
+
+    /**
+     * Tests the subMap() method.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testSubMap(String description, NavigableMap navigableMap) {
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(null, BigInteger.TEN);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(BigInteger.ZERO, null);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(null, null);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        Object obj1 = new Object();
+        Object obj2 = new Object();
+
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(obj1, BigInteger.TEN);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(BigInteger.ZERO, obj2);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        assertThrows(
+            () -> {
+                SortedMap ss = navigableMap.subMap(obj1, obj2);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        // minimal range
+        navigableMap.subMap(BigInteger.ZERO, false, BigInteger.ZERO, false);
+        navigableMap.subMap(BigInteger.ZERO, false, BigInteger.ZERO, true);
+        navigableMap.subMap(BigInteger.ZERO, true, BigInteger.ZERO, false);
+        navigableMap.subMap(BigInteger.ZERO, true, BigInteger.ZERO, true);
+
+        Object first = isDescending(navigableMap) ? BigInteger.TEN : BigInteger.ZERO;
+        Object last = (BigInteger.ZERO == first) ? BigInteger.TEN : BigInteger.ZERO;
+
+            assertThrows(
+                () -> {
+                    navigableMap.subMap(last, true, first, false);
+                },
+                IllegalArgumentException.class, description
+                + ": Must throw IllegalArgumentException when fromElement is not less then then toElement.");
+
+        navigableMap.subMap(first, true, last, false);
+    }
+
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testSubMapRanges(String description, NavigableMap navigableMap) {
+        Object first = isDescending(navigableMap) ? BigInteger.TEN : BigInteger.ZERO;
+        Object last = (BigInteger.ZERO == first) ? BigInteger.TEN : BigInteger.ZERO;
+
+        NavigableMap subMap = navigableMap.subMap(first, true, last, true);
+
+        // same subset
+        subMap.subMap(first, true, last, true);
+
+        // slightly smaller
+        NavigableMap ns = subMap.subMap(first, false, last, false);
+        // slight exapansion
+        assertThrows(() -> {
+            ns.subMap(first, true, last, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subMap.subMap(first, false, BigInteger.ONE, false);
+    }
+
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testheadMapRanges(String description, NavigableMap navigableMap) {
+        NavigableMap subMap = navigableMap.headMap(BigInteger.ONE, true);
+
+        // same subset
+        subMap.headMap(BigInteger.ONE, true);
+
+        // slightly smaller
+        NavigableMap ns = subMap.headMap(BigInteger.ONE, false);
+
+        // slight exapansion
+        assertThrows(() -> {
+            ns.headMap(BigInteger.ONE, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subMap.headMap(isDescending(subMap) ? BigInteger.TEN : BigInteger.ZERO, true);
+    }
+
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testTailMapRanges(String description, NavigableMap navigableMap) {
+        NavigableMap subMap = navigableMap.tailMap(BigInteger.ONE, true);
+
+        // same subset
+        subMap.tailMap(BigInteger.ONE, true);
+
+        // slightly smaller
+        NavigableMap ns = subMap.tailMap(BigInteger.ONE, false);
+
+        // slight exapansion
+        assertThrows(() -> {
+            ns.tailMap(BigInteger.ONE, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subMap.tailMap(isDescending(subMap) ? BigInteger.ZERO : BigInteger.TEN, false);
+    }
+
+    /**
+     * Tests the tailMap() method.
+     */
+    @Test(dataProvider = "NavigableMap<?,?>", dataProviderClass = EmptyNavigableMap.class)
+    public void testTailMap(String description, NavigableMap navigableMap) {
+        assertThrows(() -> {
+            navigableMap.tailMap(null);
+        },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(() -> {
+            navigableMap.tailMap(new Object());
+        }, ClassCastException.class);
+
+        NavigableMap ss = navigableMap.tailMap("1", true);
+
+        assertEmptyNavigableMap(ss, description + ": Returned value is not empty navigable set.");
+    }
+
+    @DataProvider(name = "NavigableMap<?,?>", parallel = true)
+    public static Iterator<Object[]> navigableMapsProvider() {
+        return makeNavigableMaps().iterator();
+    }
+
+    public static Collection<Object[]> makeNavigableMaps() {
+        return Arrays.asList(
+            new Object[]{"UnmodifiableNavigableMap(TreeMap)", Collections.unmodifiableNavigableMap(new TreeMap())},
+            new Object[]{"UnmodifiableNavigableMap(TreeMap.descendingMap()", Collections.unmodifiableNavigableMap(new TreeMap().descendingMap())},
+            new Object[]{"UnmodifiableNavigableMap(TreeMap.descendingMap().descendingMap()", Collections.unmodifiableNavigableMap(new TreeMap().descendingMap().descendingMap())},
+            new Object[]{"emptyNavigableMap()", Collections.emptyNavigableMap()},
+            new Object[]{"emptyNavigableMap().descendingMap()", Collections.emptyNavigableMap().descendingMap()},
+            new Object[]{"emptyNavigableMap().descendingMap().descendingMap()", Collections.emptyNavigableMap().descendingMap().descendingMap()}
+        );
+    }
+}
diff --git a/test/java/util/Collections/EmptyNavigableSet.java b/test/java/util/Collections/EmptyNavigableSet.java
new file mode 100644
index 0000000000000000000000000000000000000000..7c4811bdfe849c016be55f0ce0242c348f87e0e8
--- /dev/null
+++ b/test/java/util/Collections/EmptyNavigableSet.java
@@ -0,0 +1,410 @@
+/*
+ * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 4533691 7129185
+ * @summary Unit test for Collections.emptyNavigableSet
+ * @run testng EmptyNavigableSet
+ */
+import java.math.BigInteger;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.NavigableSet;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertSame;
+
+public class EmptyNavigableSet {
+
+    public static <T> void assertInstance(T actual, Class<? extends T> expected) {
+        assertInstance(expected.isInstance(actual), null);
+    }
+
+    public static <T> void assertInstance(T actual, Class<? extends T> expected, String message) {
+        assertTrue(expected.isInstance(actual), ((null != message) ? message : "")
+            + " " + (actual == null ? "<null>" : actual.getClass().getSimpleName()) + " != " + expected.getSimpleName() + ". ");
+    }
+
+    public static <T extends Throwable> void assertEmptyNavigableSet(Object obj) {
+        assertInstance(obj, NavigableSet.class);
+        assertTrue(((NavigableSet)obj).isEmpty() && (((NavigableSet)obj).size() == 0));
+    }
+
+    public static <T extends Throwable> void assertEmptyNavigableSet(Object obj, String message) {
+        assertInstance(obj, NavigableSet.class, message);
+        assertTrue(((NavigableSet)obj).isEmpty() && (((NavigableSet)obj).size() == 0),
+            ((null != message) ? message : "") + " Not empty. ");
+    }
+
+    public interface Thrower<T extends Throwable> {
+
+        public void run() throws T;
+    }
+
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable) {
+        assertThrows(thrower, throwable, null);
+    }
+
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable, String message) {
+        Throwable result;
+        try {
+            thrower.run();
+            fail(((null != message) ? message : "") + "Failed to throw " + throwable.getCanonicalName() + ". ");
+            return;
+        } catch (Throwable caught) {
+            result = caught;
+        }
+
+        assertInstance(result, throwable, ((null != message) ? message : "") + "Failed to throw " + throwable.getCanonicalName() + ". ");
+    }
+
+    public static final boolean isDescending(SortedSet<?> set) {
+        if (null == set.comparator()) {
+            // natural order
+            return false;
+        }
+
+        if (Collections.reverseOrder() == set.comparator()) {
+            // reverse natural order.
+            return true;
+        }
+
+        if (set.comparator().equals(Collections.reverseOrder(Collections.reverseOrder(set.comparator())))) {
+            // it's a Collections.reverseOrder(Comparator).
+            return true;
+        }
+
+        throw new IllegalStateException("can't determine ordering for " + set);
+    }
+
+    /**
+     * Tests that the comparator is {@code null}.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testComparatorIsNull(String description, NavigableSet<?> navigableSet) {
+        Comparator comparator = navigableSet.comparator();
+
+        assertTrue(comparator == null || comparator == Collections.reverseOrder(), description + ": Comparator (" + comparator + ") is not null.");
+    }
+
+    /**
+     * Tests that contains requires Comparable
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testContainsRequiresComparable(String description, NavigableSet<?> navigableSet) {
+        assertThrows(() -> {
+            navigableSet.contains(new Object());
+        },
+            ClassCastException.class,
+            description + ": Compareable should be required");
+    }
+
+    /**
+     * Tests that the contains method returns {@code false}.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testContains(String description, NavigableSet<?> navigableSet) {
+        assertFalse(navigableSet.contains(new Integer(1)),
+            description + ": Should not contain any elements.");
+    }
+
+    /**
+     * Tests that the containsAll method returns {@code false}.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testContainsAll(String description, NavigableSet<?> navigableSet) {
+        TreeSet treeSet = new TreeSet();
+        treeSet.add("1");
+        treeSet.add("2");
+        treeSet.add("3");
+
+        assertFalse(navigableSet.containsAll(treeSet), "Should not contain any elements.");
+    }
+
+    /**
+     * Tests that the iterator is empty.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testEmptyIterator(String description, NavigableSet<?> navigableSet) {
+        Iterator emptyIterator = navigableSet.iterator();
+
+        assertFalse((emptyIterator != null) && (emptyIterator.hasNext()),
+            "The iterator is not empty.");
+    }
+
+    /**
+     * Tests that the set is empty.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testIsEmpty(String description, NavigableSet<?> navigableSet) {
+        assertTrue(navigableSet.isEmpty(), "The set is not empty.");
+    }
+
+    /**
+     * Tests that the first() method throws NoSuchElementException
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testFirst(String description, NavigableSet<?> navigableSet) {
+        assertThrows(() -> {
+            navigableSet.first();
+        }, NoSuchElementException.class, description);
+    }
+
+    /**
+     * Tests the headSet() method.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testHeadSet(String description, NavigableSet navigableSet) {
+        assertThrows(
+            () -> { NavigableSet ns = navigableSet.headSet(null, false); },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> { NavigableSet ns = navigableSet.headSet(new Object(), true); },
+            ClassCastException.class,
+            description + ": Must throw ClassCastException for non-Comparable element");
+
+        NavigableSet ns = navigableSet.headSet("1", false);
+
+        assertEmptyNavigableSet(ns, description + ": Returned value is not empty navigable set.");
+    }
+
+    /**
+     * Tests that the last() method throws NoSuchElementException
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testLast(String description, NavigableSet<?> navigableSet) {
+        assertThrows(() -> {
+            navigableSet.last();
+        }, NoSuchElementException.class, description);
+    }
+
+    /**
+     * Tests that the size is 0.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testSizeIsZero(String description, NavigableSet<?> navigableSet) {
+        assertTrue(0 == navigableSet.size(), "The size of the set is not 0.");
+    }
+
+    /**
+     * Tests the subSet() method.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testSubSet(String description, NavigableSet navigableSet) {
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(null, BigInteger.TEN);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(BigInteger.ZERO, null);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(null, null);
+            },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        Object obj1 = new Object();
+        Object obj2 = new Object();
+
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(obj1, BigInteger.TEN);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(BigInteger.ZERO, obj2);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        assertThrows(
+            () -> {
+                SortedSet ss = navigableSet.subSet(obj1, obj2);
+            },
+            ClassCastException.class, description
+            + ": Must throw ClassCastException for parameter which is not Comparable.");
+
+        // minimal range
+        navigableSet.subSet(BigInteger.ZERO, false, BigInteger.ZERO, false);
+        navigableSet.subSet(BigInteger.ZERO, false, BigInteger.ZERO, true);
+        navigableSet.subSet(BigInteger.ZERO, true, BigInteger.ZERO, false);
+        navigableSet.subSet(BigInteger.ZERO, true, BigInteger.ZERO, true);
+
+        Object first = isDescending(navigableSet) ? BigInteger.TEN : BigInteger.ZERO;
+        Object last = (BigInteger.ZERO == first) ? BigInteger.TEN : BigInteger.ZERO;
+
+            assertThrows(
+                () -> {
+                    navigableSet.subSet(last, true, first, false);
+                },
+                IllegalArgumentException.class, description
+                + ": Must throw IllegalArgumentException when fromElement is not less then then toElement.");
+
+        navigableSet.subSet(first, true, last, false);
+    }
+
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testSubSetRanges(String description, NavigableSet navigableSet) {
+        Object first = isDescending(navigableSet) ? BigInteger.TEN : BigInteger.ZERO;
+        Object last = (BigInteger.ZERO == first) ? BigInteger.TEN : BigInteger.ZERO;
+
+        NavigableSet subSet = navigableSet.subSet(first, true, last, true);
+
+        // same subset
+        subSet.subSet(first, true, last, true);
+
+        // slightly smaller
+        NavigableSet ns = subSet.subSet(first, false, last, false);
+        // slight exapansion
+        assertThrows(() -> {
+            ns.subSet(first, true, last, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subSet.subSet(first, false, BigInteger.ONE, false);
+    }
+
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testheadSetRanges(String description, NavigableSet navigableSet) {
+        NavigableSet subSet = navigableSet.headSet(BigInteger.ONE, true);
+
+        // same subset
+        subSet.headSet(BigInteger.ONE, true);
+
+        // slightly smaller
+        NavigableSet ns = subSet.headSet(BigInteger.ONE, false);
+
+        // slight exapansion
+        assertThrows(() -> {
+            ns.headSet(BigInteger.ONE, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subSet.headSet(isDescending(subSet) ? BigInteger.TEN : BigInteger.ZERO, true);
+    }
+
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testTailSetRanges(String description, NavigableSet navigableSet) {
+        NavigableSet subSet = navigableSet.tailSet(BigInteger.ONE, true);
+
+        // same subset
+        subSet.tailSet(BigInteger.ONE, true);
+
+        // slightly smaller
+        NavigableSet ns = subSet.tailSet(BigInteger.ONE, false);
+
+        // slight exapansion
+        assertThrows(() -> {
+            ns.tailSet(BigInteger.ONE, true);
+        },
+            IllegalArgumentException.class,
+            description + ": Expansion should not be allowed");
+
+        // much smaller
+        subSet.tailSet(isDescending(subSet) ? BigInteger.ZERO : BigInteger.TEN, false);
+    }
+
+    /**
+     * Tests the tailSet() method.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testTailSet(String description, NavigableSet navigableSet) {
+        assertThrows(() -> {
+            navigableSet.tailSet(null);
+        },
+            NullPointerException.class,
+            description + ": Must throw NullPointerException for null element");
+
+        assertThrows(() -> {
+            navigableSet.tailSet(new Object());
+        }, ClassCastException.class);
+
+        NavigableSet ss = navigableSet.tailSet("1", true);
+
+        assertEmptyNavigableSet(ss, description + ": Returned value is not empty navigable set.");
+    }
+
+    /**
+     * Tests that the array has a size of 0.
+     */
+    @Test(dataProvider = "NavigableSet<?>", dataProviderClass = EmptyNavigableSet.class)
+    public void testToArray(String description, NavigableSet<?> navigableSet) {
+        Object[] emptyNavigableSetArray = navigableSet.toArray();
+
+        assertTrue(emptyNavigableSetArray.length == 0, "Returned non-empty Array.");
+
+        emptyNavigableSetArray = new Object[20];
+
+        Object[] result = navigableSet.toArray(emptyNavigableSetArray);
+
+        assertSame(emptyNavigableSetArray, result);
+
+        assertTrue(result[0] == null);
+    }
+
+    @DataProvider(name = "NavigableSet<?>", parallel = true)
+    public static Iterator<Object[]> navigableSetsProvider() {
+        return makeNavigableSets().iterator();
+    }
+
+    public static Collection<Object[]> makeNavigableSets() {
+        return Arrays.asList(
+            new Object[]{"UnmodifiableNavigableSet(TreeSet)", Collections.unmodifiableNavigableSet(new TreeSet())},
+            new Object[]{"UnmodifiableNavigableSet(TreeSet.descendingSet()", Collections.unmodifiableNavigableSet(new TreeSet().descendingSet())},
+            new Object[]{"UnmodifiableNavigableSet(TreeSet.descendingSet().descendingSet()", Collections.unmodifiableNavigableSet(new TreeSet().descendingSet().descendingSet())},
+            new Object[]{"emptyNavigableSet()", Collections.emptyNavigableSet()},
+            new Object[]{"emptyNavigableSet().descendingSet()", Collections.emptyNavigableSet().descendingSet()},
+            new Object[]{"emptyNavigableSet().descendingSet().descendingSet()", Collections.emptyNavigableSet().descendingSet().descendingSet()}
+        );
+    }
+}
diff --git a/test/java/util/Collections/EmptySortedSet.java b/test/java/util/Collections/EmptySortedSet.java
deleted file mode 100644
index 224400ec7a8d8e5e86f76c6a58143b96bd38a77d..0000000000000000000000000000000000000000
--- a/test/java/util/Collections/EmptySortedSet.java
+++ /dev/null
@@ -1,351 +0,0 @@
-/*
- * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/*
- * @test
- * @bug 4533691
- * @summary Unit test for Collections.emptySortedSet
- */
-
-import java.lang.reflect.Method;
-import java.math.BigInteger;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Iterator;
-import java.util.NoSuchElementException;
-import java.util.SortedSet;
-import java.util.TreeSet;
-
-public class EmptySortedSet {
-    static int status = 0;
-    private static final String FAILED = " failed. ";
-    private static final String PERIOD = ".";
-    private final String thisClassName = this.getClass().getName();
-
-    public static void main(String[] args) throws Exception {
-        new EmptySortedSet();
-    }
-
-    public EmptySortedSet() throws Exception {
-        run();
-    }
-
-    /**
-     * Returns {@code true} if the {@link Object} passed in is an empty
-     * {@link SortedSet}.
-     *
-     * @param obj the object to test
-     * @return {@code true} if the {@link Object} is an empty {@link SortedSet}
-     *         otherwise {@code false}.
-     */
-    private boolean isEmptySortedSet(Object obj) {
-        boolean isEmptySortedSet = false;
-
-        // We determine if the object is an empty sorted set by testing if it's
-        // an instance of SortedSet, and if so, if it's empty.  Currently the
-        // testing doesn't include checks of the other methods.
-        if (obj instanceof SortedSet) {
-            SortedSet ss = (SortedSet) obj;
-
-            if ((ss.isEmpty()) && (ss.size() == 0)) {
-                isEmptySortedSet = true;
-            }
-        }
-
-        return isEmptySortedSet;
-    }
-
-    private void run() throws Exception {
-        Method[] methods = this.getClass().getDeclaredMethods();
-
-        for (int i = 0; i < methods.length; i++) {
-            Method method = methods[i];
-            String methodName = method.getName();
-
-            if (methodName.startsWith("test")) {
-                try {
-                    Object obj = method.invoke(this, new Object[0]);
-                } catch(Exception e) {
-                    throw new Exception(this.getClass().getName() + "." +
-                            methodName + " test failed, test exception "
-                            + "follows\n" + e.getCause());
-                }
-            }
-        }
-    }
-
-    private void throwException(String methodName, String reason)
-            throws Exception
-    {
-        StringBuilder sb = new StringBuilder(thisClassName);
-        sb.append(PERIOD);
-        sb.append(methodName);
-        sb.append(FAILED);
-        sb.append(reason);
-        throw new Exception(sb.toString());
-    }
-
-    /**
-     *
-     */
-    private void test00() throws Exception {
-        //throwException("test00", "This test has not been implemented yet.");
-    }
-
-    /**
-     * Tests that the comparator is {@code null}.
-     */
-    private void testComparatorIsNull() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        Comparator comparator = sortedSet.comparator();
-
-        if (comparator != null) {
-            throwException("testComparatorIsNull", "Comparator is not null.");
-        }
-    }
-
-    /**
-     * Tests that the contains method returns {@code false}.
-     */
-    private void testContains() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-
-        if (sortedSet.contains(new Object())) {
-            throwException("testContains", "Should not contain any elements.");
-        }
-    }
-
-    /**
-     * Tests that the containsAll method returns {@code false}.
-     */
-    private void testContainsAll() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        TreeSet treeSet = new TreeSet();
-        treeSet.add("1");
-        treeSet.add("2");
-        treeSet.add("3");
-
-        if (sortedSet.containsAll(treeSet)) {
-            throwException("testContainsAll",
-                    "Should not contain any elements.");
-        }
-    }
-
-    /**
-     * Tests that the iterator is empty.
-     */
-    private void testEmptyIterator() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        Iterator emptyIterator = sortedSet.iterator();
-
-        if ((emptyIterator != null) && (emptyIterator.hasNext())) {
-            throwException("testEmptyIterator", "The iterator is not empty.");
-        }
-    }
-
-    /**
-     * Tests that the set is empty.
-     */
-    private void testIsEmpty() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-
-        if ((sortedSet != null) && (!sortedSet.isEmpty())) {
-            throwException("testSizeIsZero", "The set is not empty.");
-        }
-    }
-
-    /**
-     * Tests that the first() method throws NoSuchElementException
-     */
-    private void testFirst() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-
-        try {
-            sortedSet.first();
-            throwException("testFirst",
-                    "NoSuchElemenException was not thrown.");
-        } catch(NoSuchElementException nsee) {
-            // Do nothing
-        }
-    }
-
-    /**
-     * Tests the headSet() method.
-     */
-    private void testHeadSet() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        SortedSet ss;
-
-        try {
-            ss = sortedSet.headSet(null);
-            throwException("testHeadSet",
-                    "Must throw NullPointerException for null element");
-        } catch(NullPointerException npe) {
-            // Do nothing
-        }
-
-        try {
-            ss = sortedSet.headSet(new Object());
-            throwException("testHeadSet",
-                    "Must throw ClassCastException for non-Comparable element");
-        } catch(ClassCastException cce) {
-            // Do nothing.
-        }
-
-        ss = sortedSet.headSet("1");
-
-        if ((ss == null) || !isEmptySortedSet(ss)) {
-            throwException("testHeadSet",
-                    "Returned value is null or not an EmptySortedSet.");
-        }
-    }
-
-    /**
-     * Tests that the last() method throws NoSuchElementException
-     */
-    private void testLast() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-
-        try {
-            sortedSet.last();
-            throwException("testLast",
-                    "NoSuchElemenException was not thrown.");
-        } catch(NoSuchElementException nsee) {
-            // Do nothing
-        }
-    }
-
-    /**
-     * Tests that the size is 0.
-     */
-    private void testSizeIsZero() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        int size = sortedSet.size();
-
-        if (size > 0) {
-            throwException("testSizeIsZero",
-                    "The size of the set is greater then 0.");
-        }
-    }
-
-    /**
-     * Tests the subSet() method.
-     */
-    private void testSubSet() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        SortedSet ss = sortedSet.headSet("1");
-
-        try {
-            ss = sortedSet.subSet(null, BigInteger.TEN);
-            ss = sortedSet.subSet(BigInteger.ZERO, null);
-            ss = sortedSet.subSet(null, null);
-            throwException("testSubSet",
-                    "Must throw NullPointerException for null element");
-        } catch(NullPointerException npe) {
-            // Do nothing
-        }
-
-        try {
-            Object obj1 = new Object();
-            Object obj2 = new Object();
-            ss = sortedSet.subSet(obj1, BigInteger.TEN);
-            ss = sortedSet.subSet(BigInteger.ZERO, obj2);
-            ss = sortedSet.subSet(obj1, obj2);
-            throwException("testSubSet",
-                    "Must throw ClassCastException for parameter which is "
-                    + "not Comparable.");
-        } catch(ClassCastException cce) {
-            // Do nothing.
-        }
-
-        try {
-            ss = sortedSet.subSet(BigInteger.ZERO, BigInteger.ZERO);
-            ss = sortedSet.subSet(BigInteger.TEN, BigInteger.ZERO);
-            throwException("testSubSet",
-                    "Must throw IllegalArgumentException when fromElement is "
-                    + "not less then then toElement.");
-        } catch(IllegalArgumentException iae) {
-            // Do nothing.
-        }
-
-        ss = sortedSet.subSet(BigInteger.ZERO, BigInteger.TEN);
-
-        if (!isEmptySortedSet(ss)) {
-            throw new Exception("Returned value is not empty sorted set.");
-        }
-    }
-
-    /**
-     * Tests the tailSet() method.
-     */
-    private void testTailSet() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        SortedSet ss;
-
-        try {
-            ss = sortedSet.tailSet(null);
-            throwException("testTailSet",
-                    "Must throw NullPointerException for null element");
-        } catch(NullPointerException npe) {
-            // Do nothing
-        }
-
-        try {
-            SortedSet ss2 = sortedSet.tailSet(new Object());
-            throwException("testTailSet",
-                    "Must throw ClassCastException for non-Comparable element");
-        } catch(ClassCastException cce) {
-            // Do nothing.
-        }
-
-        ss = sortedSet.tailSet("1");
-
-        if ((ss == null) || !isEmptySortedSet(ss)) {
-            throwException("testTailSet",
-                    "Returned value is null or not an EmptySortedSet.");
-        }
-    }
-
-    /**
-     * Tests that the array has a size of 0.
-     */
-    private void testToArray() throws Exception {
-        SortedSet sortedSet = Collections.emptySortedSet();
-        Object[] emptySortedSetArray = sortedSet.toArray();
-
-        if ((emptySortedSetArray == null) || (emptySortedSetArray.length > 0)) {
-            throwException("testToArray",
-                    "Returned null array or array with length > 0.");
-        }
-
-        String[] strings = new String[2];
-        strings[0] = "1";
-        strings[1] = "2";
-        emptySortedSetArray = sortedSet.toArray(strings);
-
-        if ((emptySortedSetArray == null) || (emptySortedSetArray[0] != null)) {
-            throwException("testToArray",
-                    "Returned null array or array with length > 0.");
-        }
-    }
-}
diff --git a/test/java/util/Map/LockStep.java b/test/java/util/Map/LockStep.java
index 553644782ce193bdbbf8ee6c24feeea8cd267e9b..2903c5a5f506d7d12a8326f76de50b700a63d787 100644
--- a/test/java/util/Map/LockStep.java
+++ b/test/java/util/Map/LockStep.java
@@ -100,7 +100,14 @@ public class LockStep {
                     new Hashtable(16),
                     new TreeMap(),
                     new ConcurrentHashMap(16),
-                    new ConcurrentSkipListMap() });
+                    new ConcurrentSkipListMap(),
+                    Collections.checkedMap(new HashMap(16), Integer.class, Integer.class),
+                    Collections.checkedSortedMap(new TreeMap(), Integer.class, Integer.class),
+                    Collections.checkedNavigableMap(new TreeMap(), Integer.class, Integer.class),
+                    Collections.synchronizedMap(new HashMap(16)),
+                    Collections.synchronizedSortedMap(new TreeMap()),
+                    Collections.synchronizedNavigableMap(new TreeMap())
+                    });
 
             for (int j = 0; j < 10; j++)
                 put(maps, r.nextInt(100), r.nextInt(100));
diff --git a/test/java/util/NavigableMap/LockStep.java b/test/java/util/NavigableMap/LockStep.java
index 64f9bdf7683bdd19d46e13aa3ad9ef9f2f7bad90..0b43d0a0744e7cc0a696efa5203cfb1bf1d41527 100644
--- a/test/java/util/NavigableMap/LockStep.java
+++ b/test/java/util/NavigableMap/LockStep.java
@@ -55,11 +55,19 @@ public class LockStep {
 
         lockSteps(new TreeMap(),
                   new ConcurrentSkipListMap());
+        lockSteps(new TreeMap(),
+                  Collections.checkedNavigableMap(new TreeMap(), Integer.class, Integer.class));
+        lockSteps(new TreeMap(),
+                  Collections.synchronizedNavigableMap(new TreeMap()));
         lockSteps(new TreeMap(reverseOrder()),
                   new ConcurrentSkipListMap(reverseOrder()));
 
         lockSteps(new TreeSet(),
                   new ConcurrentSkipListSet());
+        lockSteps(new TreeSet(),
+                  Collections.checkedNavigableSet(new TreeSet(), Integer.class));
+        lockSteps(new TreeSet(),
+                  Collections.synchronizedNavigableSet(new TreeSet()));
         lockSteps(new TreeSet(reverseOrder()),
                   new ConcurrentSkipListSet(reverseOrder()));
     }
@@ -181,7 +189,15 @@ public class LockStep {
         testEmptyCollection(m.values());
     }
 
-    static final Random rnd = new Random();
+    static final Random rnd;
+
+    static {
+        // sufficiently random for this test
+        long seed = System.nanoTime();
+        System.out.println(LockStep.class.getCanonicalName() + ": Trial random seed: " + seed );
+
+        rnd = new Random(seed);
+    }
 
     static void equalNext(final Iterator<?> it, Object expected) {
         if (maybe(2))
@@ -208,8 +224,15 @@ public class LockStep {
             check(s.descendingSet().descendingSet().comparator() == null);
         equal(s.isEmpty(), s.size() == 0);
         equal2(s, s.descendingSet());
-        if (maybe(4) && s instanceof Serializable)
-            equal2(s, serialClone(s));
+        if (maybe(4) && s instanceof Serializable) {
+            try {
+                equal2(s, serialClone(s));
+            } catch(RuntimeException uhoh) {
+                if(!(uhoh.getCause() instanceof NotSerializableException)) {
+                    throw uhoh;
+                }
+            }
+        }
         Comparator cmp = comparator(s);
         if (s.isEmpty()) {
             THROWS(NoSuchElementException.class,
@@ -276,6 +299,15 @@ public class LockStep {
         check(! it2.hasNext());
     }
 
+    static void equalSetsLeaf(final Set s1, final Set s2) {
+        equal2(s1,            s2);
+        equal( s1.size(),     s2.size());
+        equal( s1.isEmpty(),  s2.isEmpty());
+        equal( s1.hashCode(), s2.hashCode());
+        equal( s1.toString(), s2.toString());
+        equal( s1.containsAll(s2), s2.containsAll(s1));
+    }
+
     static void equalNavigableSetsLeaf(final NavigableSet s1,
                                        final NavigableSet s2) {
         equal2(s1,            s2);
@@ -448,8 +480,7 @@ public class LockStep {
     static void equalNavigableMaps(NavigableMap m1,
                                    NavigableMap m2) {
         equalNavigableMapsLeaf(m1, m2);
-        equalNavigableSetsLeaf((NavigableSet) m1.keySet(),
-                               (NavigableSet) m2.keySet());
+        equalSetsLeaf(m1.keySet(), m2.keySet());
         equalNavigableSets(m1.navigableKeySet(),
                            m2.navigableKeySet());
         equalNavigableSets(m1.descendingKeySet(),
@@ -836,5 +867,7 @@ public class LockStep {
     @SuppressWarnings("unchecked")
     static <T> T serialClone(T obj) {
         try { return (T) readObject(serializedForm(obj)); }
-        catch (Exception e) { throw new RuntimeException(e); }}
+        catch (Error|RuntimeException e) { throw e; }
+        catch (Throwable e) { throw new RuntimeException(e); }
+    }
 }
diff --git a/test/java/util/Optional/Basic.java b/test/java/util/Optional/Basic.java
index 099e045598571eb7ec9803acf2995801a26f01d9..dc05ff97a7835a906df8854a6b3155e085dea1ed 100644
--- a/test/java/util/Optional/Basic.java
+++ b/test/java/util/Optional/Basic.java
@@ -58,36 +58,36 @@ public class Basic {
         assertSame(Boolean.FALSE, empty.orElseGet(()-> Boolean.FALSE));
     }
 
-        @Test(expectedExceptions=NoSuchElementException.class)
-        public void testEmptyGet() {
-            Optional<Boolean> empty = Optional.empty();
+    @Test(expectedExceptions=NoSuchElementException.class)
+    public void testEmptyGet() {
+        Optional<Boolean> empty = Optional.empty();
 
-            Boolean got = empty.get();
-        }
+        Boolean got = empty.get();
+    }
 
-        @Test(expectedExceptions=NullPointerException.class)
-        public void testEmptyOrElseGetNull() {
-            Optional<Boolean> empty = Optional.empty();
+    @Test(expectedExceptions=NullPointerException.class)
+    public void testEmptyOrElseGetNull() {
+        Optional<Boolean> empty = Optional.empty();
 
-            Boolean got = empty.orElseGet(null);
-        }
+        Boolean got = empty.orElseGet(null);
+    }
 
-        @Test(expectedExceptions=NullPointerException.class)
-        public void testEmptyOrElseThrowNull() throws Throwable {
-            Optional<Boolean> empty = Optional.empty();
+    @Test(expectedExceptions=NullPointerException.class)
+    public void testEmptyOrElseThrowNull() throws Throwable {
+        Optional<Boolean> empty = Optional.empty();
 
-            Boolean got = empty.orElseThrow(null);
-        }
+        Boolean got = empty.orElseThrow(null);
+    }
 
-        @Test(expectedExceptions=ObscureException.class)
-        public void testEmptyOrElseThrow() throws Exception {
-            Optional<Boolean> empty = Optional.empty();
+    @Test(expectedExceptions=ObscureException.class)
+    public void testEmptyOrElseThrow() throws Exception {
+        Optional<Boolean> empty = Optional.empty();
 
-            Boolean got = empty.orElseThrow(ObscureException::new);
-        }
+        Boolean got = empty.orElseThrow(ObscureException::new);
+    }
 
-        @Test(groups = "unit")
-        public void testPresent() {
+    @Test(groups = "unit")
+    public void testPresent() {
         Optional<Boolean> empty = Optional.empty();
         Optional<String> presentEmptyString = Optional.of("");
         Optional<Boolean> present = Optional.of(Boolean.TRUE);
@@ -116,6 +116,116 @@ public class Basic {
         assertSame(Boolean.TRUE, present.<RuntimeException>orElseThrow(ObscureException::new));
     }
 
+    @Test(groups = "unit")
+    public void testOfNullable() {
+        Optional<String> instance = Optional.ofNullable(null);
+        assertFalse(instance.isPresent());
+
+        instance = Optional.ofNullable("Duke");
+        assertTrue(instance.isPresent());
+        assertEquals(instance.get(), "Duke");
+    }
+
+    @Test(groups = "unit")
+    public void testFilter() {
+        // Null mapper function
+        Optional<String> empty = Optional.empty();
+        Optional<String> duke = Optional.of("Duke");
+
+        try {
+            Optional<String> result = empty.filter(null);
+            fail("Should throw NPE on null mapping function");
+        } catch (NullPointerException npe) {
+            // expected
+        }
+
+        Optional<String> result = empty.filter(String::isEmpty);
+        assertFalse(result.isPresent());
+
+        result = duke.filter(String::isEmpty);
+        assertFalse(result.isPresent());
+        result = duke.filter(s -> s.startsWith("D"));
+        assertTrue(result.isPresent());
+        assertEquals(result.get(), "Duke");
+
+        Optional<String> emptyString = Optional.of("");
+        result = emptyString.filter(String::isEmpty);
+        assertTrue(result.isPresent());
+        assertEquals(result.get(), "");
+    }
+
+    @Test(groups = "unit")
+    public void testMap() {
+        Optional<String> empty = Optional.empty();
+        Optional<String> duke = Optional.of("Duke");
+
+        // Null mapper function
+        try {
+            Optional<Boolean> b = empty.map(null);
+            fail("Should throw NPE on null mapping function");
+        } catch (NullPointerException npe) {
+            // expected
+        }
+
+        // Map an empty value
+        Optional<Boolean> b = empty.map(String::isEmpty);
+        assertFalse(b.isPresent());
+
+        // Map into null
+        b = empty.map(n -> null);
+        assertFalse(b.isPresent());
+        b = duke.map(s -> null);
+        assertFalse(b.isPresent());
+
+        // Map to value
+        Optional<Integer> l = duke.map(String::length);
+        assertEquals(l.get().intValue(), 4);
+    }
+
+    @Test(groups = "unit")
+    public void testFlatMap() {
+        Optional<String> empty = Optional.empty();
+        Optional<String> duke = Optional.of("Duke");
+
+        // Null mapper function
+        try {
+            Optional<Boolean> b = empty.flatMap(null);
+            fail("Should throw NPE on null mapping function");
+        } catch (NullPointerException npe) {
+            // expected
+        }
+
+        // Map into null
+        try {
+            Optional<Boolean> b = duke.flatMap(s -> null);
+            fail("Should throw NPE when mapper return null");
+        } catch (NullPointerException npe) {
+            // expected
+        }
+
+        // Empty won't invoke mapper function
+        try {
+            Optional<Boolean> b = empty.flatMap(s -> null);
+            assertFalse(b.isPresent());
+        } catch (NullPointerException npe) {
+            fail("Mapper function should not be invoked");
+        }
+
+        // Map an empty value
+        Optional<Integer> l = empty.flatMap(s -> Optional.of(s.length()));
+        assertFalse(l.isPresent());
+
+        // Map to value
+        Optional<Integer> fixture = Optional.of(Integer.MAX_VALUE);
+        l = duke.flatMap(s -> Optional.of(s.length()));
+        assertTrue(l.isPresent());
+        assertEquals(l.get().intValue(), 4);
+
+        // Verify same instance
+        l = duke.flatMap(s -> fixture);
+        assertSame(l, fixture);
+    }
+
     private static class ObscureException extends RuntimeException {
 
     }
diff --git a/test/java/util/stream/bootlib/java/util/stream/LambdaTestHelpers.java b/test/java/util/stream/bootlib/java/util/stream/LambdaTestHelpers.java
index 225cbf147f659c257b9bfc4e201f9755182de856..cec872aa4841b2ade715b06d29864006d7051a71 100644
--- a/test/java/util/stream/bootlib/java/util/stream/LambdaTestHelpers.java
+++ b/test/java/util/stream/bootlib/java/util/stream/LambdaTestHelpers.java
@@ -360,35 +360,26 @@ public class LambdaTestHelpers {
     private static<T> Map<T, Integer> toBoxedMultiset(Iterator<T> it) {
         Map<Object, Integer> result = new HashMap<>();
 
-        it.forEachRemaining(new OmnivorousConsumer<T>() {
-            @Override
-            public void accept(T t) {
-                add(t);
-            }
-
-            @Override
-            public void accept(int value) {
-                add(value);
-            }
+        it.forEachRemaining(toBoxingConsumer(o -> {
+                if (result.containsKey(o))
+                    result.put(o, result.get(o) + 1);
+                else
+                    result.put(o, 1);
+            }));
 
-            @Override
-            public void accept(long value) {
-                add(value);
-            }
+        return (Map<T, Integer>) result;
+    }
 
-            @Override
-            public void accept(double value) {
-                add(value);
-            }
+    @SuppressWarnings("unchecked")
+    public static<T> Map<T, Integer> toBoxedMultiset(Spliterator<T> it) {
+        Map<Object, Integer> result = new HashMap<>();
 
-            void add(Object o) {
+        it.forEachRemaining(toBoxingConsumer(o -> {
                 if (result.containsKey(o))
                     result.put(o, result.get(o) + 1);
                 else
                     result.put(o, 1);
-            }
-
-        });
+            }));
 
         return (Map<T, Integer>) result;
     }
diff --git a/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatOpTest.java b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatOpTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..1b3c4b65bf243ef7b431d982836ee0e2556f521f
--- /dev/null
+++ b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatOpTest.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.tests.java.util.stream;
+
+import java.util.stream.OpTestCase;
+import java.util.stream.StreamTestDataProvider;
+
+import org.testng.annotations.Test;
+
+import java.util.stream.Stream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.DoubleStream;
+import java.util.stream.TestData;
+
+import static java.util.stream.LambdaTestHelpers.*;
+
+public class ConcatOpTest extends OpTestCase {
+
+    // Sanity to make sure all type of stream source works
+    @Test(dataProvider = "StreamTestData<Integer>", dataProviderClass = StreamTestDataProvider.class)
+    public void testOpsSequential(String name, TestData.OfRef<Integer> data) {
+        exerciseOpsInt(data,
+                       s -> Stream.concat(s, data.stream()),
+                       s -> IntStream.concat(s, data.stream().mapToInt(Integer::intValue)),
+                       s -> LongStream.concat(s, data.stream().mapToLong(Integer::longValue)),
+                       s -> DoubleStream.concat(s, data.stream().mapToDouble(Integer::doubleValue)));
+    }
+}
diff --git a/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatTest.java b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..4ce9c9645b648c1be91788f1e2abf27420d7ef5f
--- /dev/null
+++ b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/ConcatTest.java
@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.tests.java.util.stream;
+
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Factory;
+import org.testng.annotations.Test;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Spliterator;
+import java.util.TreeSet;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+
+import static java.util.stream.LambdaTestHelpers.*;
+import static org.testng.Assert.*;
+
+@Test
+public class ConcatTest {
+    private static Object[][] cases;
+
+    static {
+        List<Integer> part1 = Arrays.asList(5, 3, 4, 1, 2, 6, 2, 4);
+        List<Integer> part2 = Arrays.asList(8, 8, 6, 6, 9, 7, 10, 9);
+        List<Integer> p1p2 = Arrays.asList(5, 3, 4, 1, 2, 6, 2, 4, 8, 8, 6, 6, 9, 7, 10, 9);
+        List<Integer> p2p1 = Arrays.asList(8, 8, 6, 6, 9, 7, 10, 9, 5, 3, 4, 1, 2, 6, 2, 4);
+        List<Integer> empty = new LinkedList<>(); // To be ordered
+        assertTrue(empty.isEmpty());
+        LinkedHashSet<Integer> distinctP1 = new LinkedHashSet<>(part1);
+        LinkedHashSet<Integer> distinctP2 = new LinkedHashSet<>(part2);
+        TreeSet<Integer> sortedP1 = new TreeSet<>(part1);
+        TreeSet<Integer> sortedP2 = new TreeSet<>(part2);
+
+        cases = new Object[][] {
+            { "regular", part1, part2, p1p2 },
+            { "reverse regular", part2, part1, p2p1 },
+            { "front distinct", distinctP1, part2, Arrays.asList(5, 3, 4, 1, 2, 6, 8, 8, 6, 6, 9, 7, 10, 9) },
+            { "back distinct", part1, distinctP2, Arrays.asList(5, 3, 4, 1, 2, 6, 2, 4, 8, 6, 9, 7, 10) },
+            { "both distinct", distinctP1, distinctP2, Arrays.asList(5, 3, 4, 1, 2, 6, 8, 6, 9, 7, 10) },
+            { "front sorted", sortedP1, part2, Arrays.asList(1, 2, 3, 4, 5, 6, 8, 8, 6, 6, 9, 7, 10, 9) },
+            { "back sorted", part1, sortedP2, Arrays.asList(5, 3, 4, 1, 2, 6, 2, 4, 6, 7, 8, 9, 10) },
+            { "both sorted", sortedP1, sortedP2, Arrays.asList(1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10) },
+            { "reverse both sorted", sortedP2, sortedP1, Arrays.asList(6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6) },
+            { "empty something", empty, part1, part1 },
+            { "something empty", part1, empty, part1 },
+            { "empty empty", empty, empty, empty }
+        };
+    }
+
+    @DataProvider(name = "cases")
+    private static Object[][] getCases() {
+        return cases;
+    }
+
+    @Factory(dataProvider = "cases")
+    public static Object[] createTests(String scenario, Collection<Integer> c1, Collection<Integer> c2, Collection<Integer> expected) {
+        return new Object[] {
+            new ConcatTest(scenario, c1, c2, expected)
+        };
+    }
+
+    protected final String scenario;
+    protected final Collection<Integer> c1;
+    protected final Collection<Integer> c2;
+    protected final Collection<Integer> expected;
+
+    public ConcatTest(String scenario, Collection<Integer> c1, Collection<Integer> c2, Collection<Integer> expected) {
+        this.scenario = scenario;
+        this.c1 = c1;
+        this.c2 = c2;
+        this.expected = expected;
+
+        // verify prerequisite
+        Stream<Integer> s1s = c1.stream();
+        Stream<Integer> s2s = c2.stream();
+        Stream<Integer> s1p = c1.parallelStream();
+        Stream<Integer> s2p = c2.parallelStream();
+        assertTrue(s1p.isParallel());
+        assertTrue(s2p.isParallel());
+        assertFalse(s1s.isParallel());
+        assertFalse(s2s.isParallel());
+
+        assertTrue(s1s.spliterator().hasCharacteristics(Spliterator.ORDERED));
+        assertTrue(s1p.spliterator().hasCharacteristics(Spliterator.ORDERED));
+        assertTrue(s2s.spliterator().hasCharacteristics(Spliterator.ORDERED));
+        assertTrue(s2p.spliterator().hasCharacteristics(Spliterator.ORDERED));
+    }
+
+    private <T> void assertConcatContent(Spliterator<T> sp, boolean ordered, Spliterator<T> expected) {
+        // concat stream cannot guarantee uniqueness
+        assertFalse(sp.hasCharacteristics(Spliterator.DISTINCT), scenario);
+        // concat stream cannot guarantee sorted
+        assertFalse(sp.hasCharacteristics(Spliterator.SORTED), scenario);
+        // concat stream is ordered if both are ordered
+        assertEquals(sp.hasCharacteristics(Spliterator.ORDERED), ordered, scenario);
+
+        // Verify elements
+        if (ordered) {
+            assertEquals(toBoxedList(sp),
+                         toBoxedList(expected),
+                         scenario);
+        } else {
+            assertEquals(toBoxedMultiset(sp),
+                         toBoxedMultiset(expected),
+                         scenario);
+        }
+    }
+
+    private void assertRefConcat(Stream<Integer> s1, Stream<Integer> s2, boolean parallel, boolean ordered) {
+        Stream<Integer> result = Stream.concat(s1, s2);
+        assertEquals(result.isParallel(), parallel);
+        assertConcatContent(result.spliterator(), ordered, expected.spliterator());
+    }
+
+    private void assertIntConcat(Stream<Integer> s1, Stream<Integer> s2, boolean parallel, boolean ordered) {
+        IntStream result = IntStream.concat(s1.mapToInt(Integer::intValue),
+                                            s2.mapToInt(Integer::intValue));
+        assertEquals(result.isParallel(), parallel);
+        assertConcatContent(result.spliterator(), ordered,
+                            expected.stream().mapToInt(Integer::intValue).spliterator());
+    }
+
+    private void assertLongConcat(Stream<Integer> s1, Stream<Integer> s2, boolean parallel, boolean ordered) {
+        LongStream result = LongStream.concat(s1.mapToLong(Integer::longValue),
+                                              s2.mapToLong(Integer::longValue));
+        assertEquals(result.isParallel(), parallel);
+        assertConcatContent(result.spliterator(), ordered,
+                            expected.stream().mapToLong(Integer::longValue).spliterator());
+    }
+
+    private void assertDoubleConcat(Stream<Integer> s1, Stream<Integer> s2, boolean parallel, boolean ordered) {
+        DoubleStream result = DoubleStream.concat(s1.mapToDouble(Integer::doubleValue),
+                                                  s2.mapToDouble(Integer::doubleValue));
+        assertEquals(result.isParallel(), parallel);
+        assertConcatContent(result.spliterator(), ordered,
+                            expected.stream().mapToDouble(Integer::doubleValue).spliterator());
+    }
+
+    public void testRefConcat() {
+        // sequential + sequential -> sequential
+        assertRefConcat(c1.stream(), c2.stream(), false, true);
+        // parallel + parallel -> parallel
+        assertRefConcat(c1.parallelStream(), c2.parallelStream(), true, true);
+        // sequential + parallel -> parallel
+        assertRefConcat(c1.stream(), c2.parallelStream(), true, true);
+        // parallel + sequential -> parallel
+        assertRefConcat(c1.parallelStream(), c2.stream(), true, true);
+
+        // not ordered
+        assertRefConcat(c1.stream().unordered(), c2.stream(), false, false);
+        assertRefConcat(c1.stream(), c2.stream().unordered(), false, false);
+        assertRefConcat(c1.parallelStream().unordered(), c2.stream().unordered(), true, false);
+    }
+
+    public void testIntConcat() {
+        // sequential + sequential -> sequential
+        assertIntConcat(c1.stream(), c2.stream(), false, true);
+        // parallel + parallel -> parallel
+        assertIntConcat(c1.parallelStream(), c2.parallelStream(), true, true);
+        // sequential + parallel -> parallel
+        assertIntConcat(c1.stream(), c2.parallelStream(), true, true);
+        // parallel + sequential -> parallel
+        assertIntConcat(c1.parallelStream(), c2.stream(), true, true);
+
+        // not ordered
+        assertIntConcat(c1.stream().unordered(), c2.stream(), false, false);
+        assertIntConcat(c1.stream(), c2.stream().unordered(), false, false);
+        assertIntConcat(c1.parallelStream().unordered(), c2.stream().unordered(), true, false);
+    }
+
+    public void testLongConcat() {
+        // sequential + sequential -> sequential
+        assertLongConcat(c1.stream(), c2.stream(), false, true);
+        // parallel + parallel -> parallel
+        assertLongConcat(c1.parallelStream(), c2.parallelStream(), true, true);
+        // sequential + parallel -> parallel
+        assertLongConcat(c1.stream(), c2.parallelStream(), true, true);
+        // parallel + sequential -> parallel
+        assertLongConcat(c1.parallelStream(), c2.stream(), true, true);
+
+        // not ordered
+        assertLongConcat(c1.stream().unordered(), c2.stream(), false, false);
+        assertLongConcat(c1.stream(), c2.stream().unordered(), false, false);
+        assertLongConcat(c1.parallelStream().unordered(), c2.stream().unordered(), true, false);
+    }
+
+    public void testDoubleConcat() {
+        // sequential + sequential -> sequential
+        assertDoubleConcat(c1.stream(), c2.stream(), false, true);
+        // parallel + parallel -> parallel
+        assertDoubleConcat(c1.parallelStream(), c2.parallelStream(), true, true);
+        // sequential + parallel -> parallel
+        assertDoubleConcat(c1.stream(), c2.parallelStream(), true, true);
+        // parallel + sequential -> parallel
+        assertDoubleConcat(c1.parallelStream(), c2.stream(), true, true);
+
+        // not ordered
+        assertDoubleConcat(c1.stream().unordered(), c2.stream(), false, false);
+        assertDoubleConcat(c1.stream(), c2.stream().unordered(), false, false);
+        assertDoubleConcat(c1.parallelStream().unordered(), c2.stream().unordered(), true, false);
+    }
+}
diff --git a/test/java/util/stream/test/org/openjdk/tests/java/util/stream/RangeTest.java b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/RangeTest.java
index 1e6b343fc6015b5e863e2275a3453b25f042a702..20ae203bb634f99fe46241421fde08a4bd345024 100644
--- a/test/java/util/stream/test/org/openjdk/tests/java/util/stream/RangeTest.java
+++ b/test/java/util/stream/test/org/openjdk/tests/java/util/stream/RangeTest.java
@@ -226,116 +226,114 @@ public class RangeTest extends OpTestCase {
         assertEquals(first, LongStream.iterate(0, i -> i + 1).parallel().filter(i -> i > 10000).findFirst().getAsLong());
     }
 
-    // Enable when Stream.concat is present and range implementations are
-    // updated to use that
-//    private static void assertSizedAndSubSized(Spliterator<?> s) {
-//        assertTrue(s.hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED));
-//    }
-//
-//    private static void assertNotSizedAndSubSized(Spliterator<?> s) {
-//        assertFalse(s.hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED));
-//    }
-//
-//    public void testLongLongRange() {
-//        // Test [Long.MIN_VALUE, Long.MAX_VALUE)
-//        // This will concatenate streams of three ranges
-//        //   [Long.MIN_VALUE, x) [x, 0) [0, Long.MAX_VALUE)
-//        // where x = Long.divideUnsigned(0 - Long.MIN_VALUE, 2) + 1
-//        {
-//            Spliterator.OfLong s = LongStream.range(Long.MIN_VALUE, Long.MAX_VALUE).spliterator();
-//
-//            assertEquals(s.estimateSize(), Long.MAX_VALUE);
-//            assertNotSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s1 = s.trySplit();
-//            assertNotSizedAndSubSized(s1);
-//            assertSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s2 = s1.trySplit();
-//            assertSizedAndSubSized(s1);
-//            assertSizedAndSubSized(s2);
-//
-//            assertTrue(s.estimateSize() == Long.MAX_VALUE);
-//            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s2.estimateSize() < Long.MAX_VALUE);
-//
-//            assertEquals(s.estimateSize() + s1.estimateSize() + s2.estimateSize(),
-//                         Long.MAX_VALUE - Long.MIN_VALUE);
-//        }
-//
-//        long[][] ranges = { {Long.MIN_VALUE, 0}, {-1, Long.MAX_VALUE} };
-//        for (int i = 0; i < ranges.length; i++) {
-//            long start = ranges[i][0];
-//            long end = ranges[i][1];
-//
-//            Spliterator.OfLong s = LongStream.range(start, end).spliterator();
-//
-//            assertEquals(s.estimateSize(), Long.MAX_VALUE);
-//            assertNotSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s1 = s.trySplit();
-//            assertSizedAndSubSized(s1);
-//            assertSizedAndSubSized(s);
-//
-//            assertTrue(s.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
-//
-//            assertEquals(s.estimateSize() + s1.estimateSize(), end - start);
-//        }
-//    }
-//
-//    public void testLongLongRangeClosed() {
-//        // Test [Long.MIN_VALUE, Long.MAX_VALUE]
-//        // This will concatenate streams of four ranges
-//        //   [Long.MIN_VALUE, x) [x, 0) [0, y) [y, Long.MAX_VALUE]
-//        // where x = Long.divideUnsigned(0 - Long.MIN_VALUE, 2) + 1
-//        //       y = Long.divideUnsigned(Long.MAX_VALUE, 2) + 1
-//
-//        {
-//            Spliterator.OfLong s = LongStream.rangeClosed(Long.MIN_VALUE, Long.MAX_VALUE).spliterator();
-//
-//            assertEquals(s.estimateSize(), Long.MAX_VALUE);
-//            assertNotSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s1 = s.trySplit();
-//            assertNotSizedAndSubSized(s1);
-//            assertNotSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s2 = s1.trySplit();
-//            assertSizedAndSubSized(s1);
-//            assertSizedAndSubSized(s2);
-//
-//            Spliterator.OfLong s3 = s.trySplit();
-//            assertSizedAndSubSized(s3);
-//            assertSizedAndSubSized(s);
-//
-//            assertTrue(s.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s3.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s2.estimateSize() < Long.MAX_VALUE);
-//
-//            assertEquals(s.estimateSize() + s3.estimateSize() + s1.estimateSize() + s2.estimateSize(),
-//                         Long.MAX_VALUE - Long.MIN_VALUE + 1);
-//        }
-//
-//        long[][] ranges = { {Long.MIN_VALUE, 0}, {-1, Long.MAX_VALUE} };
-//        for (int i = 0; i < ranges.length; i++) {
-//            long start = ranges[i][0];
-//            long end = ranges[i][1];
-//
-//            Spliterator.OfLong s = LongStream.rangeClosed(start, end).spliterator();
-//
-//            assertEquals(s.estimateSize(), Long.MAX_VALUE);
-//            assertNotSizedAndSubSized(s);
-//
-//            Spliterator.OfLong s1 = s.trySplit();
-//            assertSizedAndSubSized(s1);
-//            assertSizedAndSubSized(s);
-//
-//            assertTrue(s.estimateSize() < Long.MAX_VALUE);
-//            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
-//
-//            assertEquals(s.estimateSize() + s1.estimateSize(), end - start + 1);
-//        }
-//    }
+    private static void assertSizedAndSubSized(Spliterator<?> s) {
+        assertTrue(s.hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED));
+    }
+
+    private static void assertNotSizedAndSubSized(Spliterator<?> s) {
+        assertFalse(s.hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED));
+    }
+
+    public void testLongLongRange() {
+        // Test [Long.MIN_VALUE, Long.MAX_VALUE)
+        // This will concatenate streams of three ranges
+        //   [Long.MIN_VALUE, x) [x, 0) [0, Long.MAX_VALUE)
+        // where x = Long.divideUnsigned(0 - Long.MIN_VALUE, 2) + 1
+        {
+            Spliterator.OfLong s = LongStream.range(Long.MIN_VALUE, Long.MAX_VALUE).spliterator();
+
+            assertEquals(s.estimateSize(), Long.MAX_VALUE);
+            assertNotSizedAndSubSized(s);
+
+            Spliterator.OfLong s1 = s.trySplit();
+            assertNotSizedAndSubSized(s1);
+            assertSizedAndSubSized(s);
+
+            Spliterator.OfLong s2 = s1.trySplit();
+            assertSizedAndSubSized(s1);
+            assertSizedAndSubSized(s2);
+
+            assertTrue(s.estimateSize() == Long.MAX_VALUE);
+            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s2.estimateSize() < Long.MAX_VALUE);
+
+            assertEquals(s.estimateSize() + s1.estimateSize() + s2.estimateSize(),
+                         Long.MAX_VALUE - Long.MIN_VALUE);
+        }
+
+        long[][] ranges = { {Long.MIN_VALUE, 0}, {-1, Long.MAX_VALUE} };
+        for (int i = 0; i < ranges.length; i++) {
+            long start = ranges[i][0];
+            long end = ranges[i][1];
+
+            Spliterator.OfLong s = LongStream.range(start, end).spliterator();
+
+            assertEquals(s.estimateSize(), Long.MAX_VALUE);
+            assertNotSizedAndSubSized(s);
+
+            Spliterator.OfLong s1 = s.trySplit();
+            assertSizedAndSubSized(s1);
+            assertSizedAndSubSized(s);
+
+            assertTrue(s.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
+
+            assertEquals(s.estimateSize() + s1.estimateSize(), end - start);
+        }
+    }
+
+    public void testLongLongRangeClosed() {
+        // Test [Long.MIN_VALUE, Long.MAX_VALUE]
+        // This will concatenate streams of four ranges
+        //   [Long.MIN_VALUE, x) [x, 0) [0, y) [y, Long.MAX_VALUE]
+        // where x = Long.divideUnsigned(0 - Long.MIN_VALUE, 2) + 1
+        //       y = Long.divideUnsigned(Long.MAX_VALUE, 2) + 1
+
+        {
+            Spliterator.OfLong s = LongStream.rangeClosed(Long.MIN_VALUE, Long.MAX_VALUE).spliterator();
+
+            assertEquals(s.estimateSize(), Long.MAX_VALUE);
+            assertNotSizedAndSubSized(s);
+
+            Spliterator.OfLong s1 = s.trySplit();
+            assertNotSizedAndSubSized(s1);
+            assertNotSizedAndSubSized(s);
+
+            Spliterator.OfLong s2 = s1.trySplit();
+            assertSizedAndSubSized(s1);
+            assertSizedAndSubSized(s2);
+
+            Spliterator.OfLong s3 = s.trySplit();
+            assertSizedAndSubSized(s3);
+            assertSizedAndSubSized(s);
+
+            assertTrue(s.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s3.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s2.estimateSize() < Long.MAX_VALUE);
+
+            assertEquals(s.estimateSize() + s3.estimateSize() + s1.estimateSize() + s2.estimateSize(),
+                         Long.MAX_VALUE - Long.MIN_VALUE + 1);
+        }
+
+        long[][] ranges = { {Long.MIN_VALUE, 0}, {-1, Long.MAX_VALUE} };
+        for (int i = 0; i < ranges.length; i++) {
+            long start = ranges[i][0];
+            long end = ranges[i][1];
+
+            Spliterator.OfLong s = LongStream.rangeClosed(start, end).spliterator();
+
+            assertEquals(s.estimateSize(), Long.MAX_VALUE);
+            assertNotSizedAndSubSized(s);
+
+            Spliterator.OfLong s1 = s.trySplit();
+            assertSizedAndSubSized(s1);
+            assertSizedAndSubSized(s);
+
+            assertTrue(s.estimateSize() < Long.MAX_VALUE);
+            assertTrue(s1.estimateSize() < Long.MAX_VALUE);
+
+            assertEquals(s.estimateSize() + s1.estimateSize(), end - start + 1);
+        }
+    }
 }