8023306: Add replace() implementations to TreeMap

Reviewed-by: psandoz, alanb, chegar, bpb

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

@@ -972,6 +972,27 @@ public class TreeMap<K,V>
         return tailMap(fromKey, true);
     }
 
+    @Override
+    public boolean replace(K key, V oldValue, V newValue) {
+        Entry<K,V> p = getEntry(key);
+        if (p!=null && Objects.equals(oldValue, p.value)) {
+            p.value = newValue;
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public V replace(K key, V value) {
+        Entry<K,V> p = getEntry(key);
+        if (p!=null) {
+            V oldValue = p.value;
+            p.value = value;
+            return oldValue;
+        }
+        return null;
+    }
+
     @Override
     public void forEach(BiConsumer<? super K, ? super V> action) {
         Objects.requireNonNull(action);