Index: /applications/editors/josm/plugins/tageditor/src/org/openstreetmap/josm/plugins/tageditor/ac/AutoCompletionListViewer.java
===================================================================
--- /applications/editors/josm/plugins/tageditor/src/org/openstreetmap/josm/plugins/tageditor/ac/AutoCompletionListViewer.java	(revision 33019)
+++ /applications/editors/josm/plugins/tageditor/src/org/openstreetmap/josm/plugins/tageditor/ac/AutoCompletionListViewer.java	(revision 33020)
@@ -32,5 +32,5 @@
 
     /** the listeners */
-    private ArrayList<IAutoCompletionListListener> listener = null;
+    private final ArrayList<IAutoCompletionListListener> listener = new ArrayList<>();
 
     /**
@@ -94,5 +94,4 @@
         this.autoCompletionList = list;
         createGUI();
-        listener = new ArrayList<>();
     }
 
@@ -103,5 +102,4 @@
         this.autoCompletionList = null;
         createGUI();
-        listener = new ArrayList<>();
     }