Index: trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 8734)
+++ trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 8735)
@@ -480,7 +480,7 @@
     @Override
     public Map<String, String> getKeys() {
+        String[] keys = this.keys;
         final Map<String, String> result = new HashMap<>(
-                Utils.hashMapInitialCapacity(this.keys == null ? 0 : this.keys.length / 2));
-        String[] keys = this.keys;
+                Utils.hashMapInitialCapacity(keys == null ? 0 : keys.length / 2));
         if (keys != null) {
             for (int i = 0; i < keys.length; i += 2) {