Index: src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java
===================================================================
--- src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java	(revision 16713)
+++ src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java	(working copy)
@@ -407,7 +407,10 @@
     public static JsonArray getHandlersInfoAsJSON(Collection<String> handlers) {
         JsonArrayBuilder json = Json.createArrayBuilder();
         for (String s : Utils.firstNonNull(handlers, RequestProcessor.handlers.keySet())) {
-            json.add(getHandlerInfoAsJSON(s));
+            JsonObject infoAsJson = getHandlerInfoAsJSON(s);
+            if (infoAsJson != null) {
+                json.add(infoAsJson);
+            }
         }
         return json.build();
     }