Index: /trunk/src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java	(revision 15719)
+++ /trunk/src/org/openstreetmap/josm/io/remotecontrol/RequestProcessor.java	(revision 15720)
@@ -494,8 +494,8 @@
             }
             if (mandatory != null && mandatory.length > 0) {
-                usage.append("<br/>mandatory parameters: ").append(Utils.join(", ", Arrays.asList(mandatory)));
+                usage.append("<br/>mandatory parameters: ").append(String.join(", ", mandatory))
             }
             if (optional != null && optional.length > 0) {
-                usage.append("<br/>optional parameters: ").append(Utils.join(", ", Arrays.asList(optional)));
+                usage.append("<br/>optional parameters: ").append(String.join(", ", optional));
             }
             if (examples != null && examples.length > 0) {
Index: /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/ImageryHandler.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/ImageryHandler.java	(revision 15719)
+++ /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/ImageryHandler.java	(revision 15720)
@@ -131,5 +131,5 @@
     @Override
     public String[] getUsageExamples() {
-        final String types = Utils.join("|", Utils.transform(Arrays.asList(ImageryInfo.ImageryType.values()),
+        final String types = String.join("|", Utils.transform(Arrays.asList(ImageryInfo.ImageryType.values()),
                 ImageryType::getTypeString));
         return new String[] {
Index: /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/RequestHandler.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/RequestHandler.java	(revision 15719)
+++ /trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/RequestHandler.java	(revision 15720)
@@ -279,5 +279,5 @@
             throw new RequestHandlerBadRequestException(
                     tr("The following keys are mandatory, but have not been provided: {0}",
-                            Utils.join(", ", missingKeys)));
+                            String.join(", ", missingKeys)));
         }
     }