Index: trunk/src/org/openstreetmap/josm/data/osm/Storage.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/Storage.java	(revision 17859)
+++ trunk/src/org/openstreetmap/josm/data/osm/Storage.java	(revision 17860)
@@ -9,4 +9,5 @@
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.Set;
 
@@ -402,10 +403,10 @@
             @Override
             public int getHashCode(O t) {
-                return t.hashCode();
+                return Objects.hashCode(t);
             }
 
             @Override
             public boolean equals(O t1, O t2) {
-                return t1.equals(t2);
+                return Objects.equals(t1, t2);
             }
         };