Index: /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java
===================================================================
--- /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java	(revision 32717)
+++ /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java	(revision 32718)
@@ -196,4 +196,6 @@
                     .flatMap(chunk -> getWikidataForArticles(wikipediaLang, chunk).entrySet().stream())
                     .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        } else if (articles.isEmpty()) {
+            return Collections.emptyMap();
         }
         try {
@@ -256,4 +258,6 @@
                     .flatMap(chunk -> getLabelForWikidata(chunk, locale, preferredLanguage).stream())
                     .collect(Collectors.toList());
+        } else if (entries.isEmpty()) {
+            return Collections.emptyList();
         }
         try {