diff -r 88540bb74300 -r 0cb657a2b888 rt/emul/mini/src/main/java/java/lang/Class.java
--- a/rt/emul/mini/src/main/java/java/lang/Class.java	Mon Mar 25 16:16:30 2013 +0100
+++ b/rt/emul/mini/src/main/java/java/lang/Class.java	Fri Apr 05 10:41:07 2013 +0200
@@ -1252,6 +1252,7 @@
     }
     
     @JavaScriptBody(args = { "sig" }, body = 
+        "if (!sig) sig = '[Ljava/lang/Object;';\n" +
         "var c = Array[sig];\n" +
         "if (c) return c;\n" +
         "c = vm.java_lang_Class(true);\n" +