diff -r 3884815c0629 -r fd38bdad7fb5 emul/src/main/java/java/lang/Class.java
--- a/emul/src/main/java/java/lang/Class.java	Sat Dec 15 08:17:45 2012 +0100
+++ b/emul/src/main/java/java/lang/Class.java	Tue Dec 18 16:04:37 2012 +0100
@@ -1090,10 +1090,12 @@
         throw new UnsupportedOperationException();
     }
 
-    static Class getPrimitiveClass(String type) {
-        // XXX
-        return Object.class;
-    }
+    @JavaScriptBody(args = "type", body = ""
+        + "var c = vm.java_lang_Class(true);"
+        + "c.jvmName = type;"
+        + "return c;"
+    )
+    native static Class getPrimitiveClass(String type);
 
     public boolean desiredAssertionStatus() {
         return false;