Make the Interface class final.

@@ -27,7 +27,7 @@ public abstract class Console<C extends RhinoContainer> extends ScriptableObject
         return sargs;
     }
 
-    public static class Interface {
+    public static final class Interface {
         public static void log(Context cx, Scriptable thisObj, Object[] args, Function funObj) {
             ((Console) thisObj).log(cx, args, funObj);
         }