Index: applications/editors/josm/plugins/wmsplugin/src/wmsplugin/AddWMSLayerPanel.java
===================================================================
--- applications/editors/josm/plugins/wmsplugin/src/wmsplugin/AddWMSLayerPanel.java	(revision 22963)
+++ applications/editors/josm/plugins/wmsplugin/src/wmsplugin/AddWMSLayerPanel.java	(revision 22964)
@@ -186,5 +186,5 @@
         if(serviceUrl.getQuery() != null) {
             a.append(serviceUrl.getQuery());
-            if (!serviceUrl.getQuery().endsWith("&")) {
+            if (!serviceUrl.getQuery().isEmpty() && !serviceUrl.getQuery().endsWith("&")) {
                 a.append("&");
             }