PMD: AbstractReferenceMap.SoftRef implements hashCode() but not equals()

src/changes/changes.xml

@@ -106,6 +106,9 @@
     <action type="fix" dev="ggregory" due-to="Marc Wrobel">
       Fix minor typos #323
     </action>
+    <action type="fix" dev="ggregory" due-to="Gary Gregory">
+      AbstractReferenceMap.SoftRef implements hashCode() but not equals().
+    </action>
     <!-- ADD -->
     <action issue="COLLECTIONS-760" dev="kinow" type="add" due-to="Isira Seneviratne">
       Add tests for MapUtils.

src/main/java/org/apache/commons/collections4/map/AbstractReferenceMap.java

@@ -966,6 +966,21 @@ public abstract class AbstractReferenceMap<K, V> extends AbstractHashedMap<K, V>
         public int hashCode() {
             return hash;
         }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (obj == null) {
+                return false;
+            }
+            if (getClass() != obj.getClass()) {
+                return false;
+            }
+            SoftRef<?> other = (SoftRef<?>) obj;
+            return hash == other.hash;
+        }
     }
 
     /**