Index: /applications/editors/josm/plugins/roadsigns/src/org/openstreetmap/josm/plugins/roadsigns/RoadSignsPlugin.java
===================================================================
--- /applications/editors/josm/plugins/roadsigns/src/org/openstreetmap/josm/plugins/roadsigns/RoadSignsPlugin.java	(revision 35934)
+++ /applications/editors/josm/plugins/roadsigns/src/org/openstreetmap/josm/plugins/roadsigns/RoadSignsPlugin.java	(revision 35935)
@@ -199,5 +199,6 @@
                 customIconDirs.add("resource://images/");
             }
-            presetsData.add(new PresetMetaData("custom", tr("custom"), customFile, Utils.join(",", customIconDirs)));
+            presetsData.add(new PresetMetaData("custom", tr("custom"), customFile,
+                    String.join(",", customIconDirs)));
         } else {
             Config.getPref().put("plugin.roadsigns.sources.last", null);