8035284: Remove redundant initializations to null

Reviewed-by: lancea, martin, chegar, shade

src/share/classes/java/util/AbstractMap.java

@@ -305,8 +305,8 @@ public abstract class AbstractMap<K,V> implements Map<K,V> {
      * appropriate view the first time this view is requested.  The views are
      * stateless, so there's no reason to create more than one of each.
      */
-    transient volatile Set<K>        keySet = null;
-    transient volatile Collection<V> values = null;
+    transient volatile Set<K>        keySet;
+    transient volatile Collection<V> values;
 
     /**
      * {@inheritDoc}

src/share/classes/java/util/Collections.java

@@ -1466,9 +1466,9 @@ public class Collections {
             throw new UnsupportedOperationException();
         }
 
-        private transient Set<K> keySet = null;
-        private transient Set<Map.Entry<K,V>> entrySet = null;
-        private transient Collection<V> values = null;
+        private transient Set<K> keySet;
+        private transient Set<Map.Entry<K,V>> entrySet;
+        private transient Collection<V> values;
 
         public Set<K> keySet() {
             if (keySet==null)
@@ -2597,9 +2597,9 @@ public class Collections {
             synchronized (mutex) {m.clear();}
         }
 
-        private transient Set<K> keySet = null;
-        private transient Set<Map.Entry<K,V>> entrySet = null;
-        private transient Collection<V> values = null;
+        private transient Set<K> keySet;
+        private transient Set<Map.Entry<K,V>> entrySet;
+        private transient Collection<V> values;
 
         public Set<K> keySet() {
             synchronized (mutex) {
@@ -3082,7 +3082,7 @@ public class Collections {
             return c.add(e);
         }
 
-        private E[] zeroLengthElementArray = null; // Lazily initialized
+        private E[] zeroLengthElementArray; // Lazily initialized
 
         private E[] zeroLengthElementArray() {
             return zeroLengthElementArray != null ? zeroLengthElementArray :
@@ -3643,7 +3643,7 @@ public class Collections {
                 m.put(e.getKey(), e.getValue());
         }
 
-        private transient Set<Map.Entry<K,V>> entrySet = null;
+        private transient Set<Map.Entry<K,V>> entrySet;
 
         public Set<Map.Entry<K,V>> entrySet() {
             if (entrySet==null)
@@ -4877,9 +4877,9 @@ public class Collections {
         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;
-        private transient Collection<V> values = null;
+        private transient Set<K> keySet;
+        private transient Set<Map.Entry<K,V>> entrySet;
+        private transient Collection<V> values;
 
         public Set<K> keySet() {
             if (keySet==null)

src/share/classes/java/util/EnumMap.java

@@ -367,7 +367,7 @@ public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V>
      * view the first time this view is requested.  The view is stateless,
      * so there's no reason to create more than one.
      */
-    private transient Set<Map.Entry<K,V>> entrySet = null;
+    private transient Set<Map.Entry<K,V>> entrySet;
 
     /**
      * Returns a {@link Set} view of the keys contained in this map.
@@ -562,7 +562,7 @@ public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V>
     }
 
     private class EntryIterator extends EnumMapIterator<Map.Entry<K,V>> {
-        private Entry lastReturnedEntry = null;
+        private Entry lastReturnedEntry;
 
         public Map.Entry<K,V> next() {
             if (!hasNext())

src/share/classes/java/util/Hashtable.java

@@ -617,9 +617,9 @@ public class Hashtable<K,V>
      * appropriate view the first time this view is requested.  The views are
      * stateless, so there's no reason to create more than one of each.
      */
-    private transient volatile Set<K> keySet = null;
-    private transient volatile Set<Map.Entry<K,V>> entrySet = null;
-    private transient volatile Collection<V> values = null;
+    private transient volatile Set<K> keySet;
+    private transient volatile Set<Map.Entry<K,V>> entrySet;
+    private transient volatile Collection<V> values;
 
     /**
      * Returns a {@link Set} view of the keys contained in this map.
@@ -1303,8 +1303,8 @@ public class Hashtable<K,V>
     private class Enumerator<T> implements Enumeration<T>, Iterator<T> {
         Entry<?,?>[] table = Hashtable.this.table;
         int index = table.length;
-        Entry<?,?> entry = null;
-        Entry<?,?> lastReturned = null;
+        Entry<?,?> entry;
+        Entry<?,?> lastReturned;
         int type;
 
         /**

src/share/classes/java/util/IdentityHashMap.java

@@ -842,7 +842,7 @@ public class IdentityHashMap<K,V>
     private class EntryIterator
         extends IdentityHashMapIterator<Map.Entry<K,V>>
     {
-        private Entry lastReturnedEntry = null;
+        private Entry lastReturnedEntry;
 
         public Map.Entry<K,V> next() {
             lastReturnedEntry = new Entry(nextIndex());
@@ -928,7 +928,7 @@ public class IdentityHashMap<K,V>
      * view the first time this view is requested.  The view is stateless,
      * so there's no reason to create more than one.
      */
-    private transient Set<Map.Entry<K,V>> entrySet = null;
+    private transient Set<Map.Entry<K,V>> entrySet;
 
     /**
      * Returns an identity-based set view of the keys contained in this map.

src/share/classes/java/util/LinkedList.java

@@ -869,7 +869,7 @@ public class LinkedList<E>
     }
 
     private class ListItr implements ListIterator<E> {
-        private Node<E> lastReturned = null;
+        private Node<E> lastReturned;
         private Node<E> next;
         private int nextIndex;
         private int expectedModCount = modCount;

src/share/classes/java/util/TreeMap.java

@@ -120,7 +120,7 @@ public class TreeMap<K,V>
      */
     private final Comparator<? super K> comparator;
 
-    private transient Entry<K,V> root = null;
+    private transient Entry<K,V> root;
 
     /**
      * The number of entries in the tree
@@ -784,9 +784,9 @@ public class TreeMap<K,V>
      * the first time this view is requested.  Views are stateless, so
      * there's no reason to create more than one.
      */
-    private transient EntrySet entrySet = null;
-    private transient KeySet<K> navigableKeySet = null;
-    private transient NavigableMap<K,V> descendingMap = null;
+    private transient EntrySet entrySet;
+    private transient KeySet<K> navigableKeySet;
+    private transient NavigableMap<K,V> descendingMap;
 
     /**
      * Returns a {@link Set} view of the keys contained in this map.
@@ -1585,9 +1585,9 @@ public class TreeMap<K,V>
         }
 
         // Views
-        transient NavigableMap<K,V> descendingMapView = null;
-        transient EntrySetView entrySetView = null;
-        transient KeySet<K> navigableKeySetView = null;
+        transient NavigableMap<K,V> descendingMapView;
+        transient EntrySetView entrySetView;
+        transient KeySet<K> navigableKeySetView;
 
         public final NavigableSet<K> navigableKeySet() {
             KeySet<K> nksv = navigableKeySetView;
@@ -2048,8 +2048,8 @@ public class TreeMap<K,V>
     static final class Entry<K,V> implements Map.Entry<K,V> {
         K key;
         V value;
-        Entry<K,V> left = null;
-        Entry<K,V> right = null;
+        Entry<K,V> left;
+        Entry<K,V> right;
         Entry<K,V> parent;
         boolean color = BLACK;
 

src/share/classes/java/util/WeakHashMap.java

@@ -759,21 +759,21 @@ public class WeakHashMap<K,V>
 
     private abstract class HashIterator<T> implements Iterator<T> {
         private int index;
-        private Entry<K,V> entry = null;
-        private Entry<K,V> lastReturned = null;
+        private Entry<K,V> entry;
+        private Entry<K,V> lastReturned;
         private int expectedModCount = modCount;
 
         /**
          * Strong reference needed to avoid disappearance of key
          * between hasNext and next
          */
-        private Object nextKey = null;
+        private Object nextKey;
 
         /**
          * Strong reference needed to avoid disappearance of key
          * between nextEntry() and any use of the entry
          */
-        private Object currentKey = null;
+        private Object currentKey;
 
         HashIterator() {
             index = isEmpty() ? 0 : table.length;
@@ -848,7 +848,7 @@ public class WeakHashMap<K,V>
 
     // Views
 
-    private transient Set<Map.Entry<K,V>> entrySet = null;
+    private transient Set<Map.Entry<K,V>> entrySet;
 
     /**
      * Returns a {@link Set} view of the keys contained in this map.