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 6218)
+++ /trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/Multipolygon.java	(revision 6219)
@@ -5,5 +5,4 @@
 import java.awt.geom.Path2D.Double;
 import java.awt.geom.PathIterator;
-import java.awt.geom.Point2D;
 import java.awt.geom.Rectangle2D;
 import java.util.ArrayList;
@@ -297,5 +296,5 @@
                     Way w = (Way) ds.getPrimitiveById(wayIds.iterator().next(), OsmPrimitiveType.WAY);
                     nodes.addAll(w.getNodes());
-                } else {
+                } else if (!wayIds.isEmpty()) {
                     List<Way> waysToJoin = new ArrayList<Way>();
                     for (Long wayId : wayIds) {
@@ -305,5 +304,7 @@
                         }
                     }
-                    nodes.addAll(joinWays(waysToJoin).iterator().next().getNodes());
+                    if (!waysToJoin.isEmpty()) {
+                        nodes.addAll(joinWays(waysToJoin).iterator().next().getNodes());
+                    }
                 }
                 resetPoly();