Index: trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/Multipolygon.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/Multipolygon.java	(revision 7294)
+++ trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/Multipolygon.java	(revision 7295)
@@ -411,6 +411,5 @@
     }
 
-    public static Collection<JoinedWay> joinWays(Collection<Way> waysToJoin)
-    {
+    public static Collection<JoinedWay> joinWays(Collection<Way> waysToJoin) {
         final Collection<JoinedWay> result = new ArrayList<>();
         final Way[] joinArray = waysToJoin.toArray(new Way[waysToJoin.size()]);
@@ -427,4 +426,7 @@
                     if (joinArray[i] != null) {
                         Way c = joinArray[i];
+                        if (c.getNodesCount() == 0) {
+                            continue;
+                        }
                         if (w == null) {
                             w = c;