Index: trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 17588)
+++ trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 17589)
@@ -448,4 +448,5 @@
     @Override
     public void visitKeys(KeyValueVisitor visitor) {
+        String[] keys = this.keys;
         if (keys != null) {
             for (int i = 0; i < keys.length; i += 2) {
@@ -647,4 +648,5 @@
     @Override
     public final Collection<String> keySet() {
+        String[] keys = this.keys;
         if (keys == null) {
             return Collections.emptySet();