diff -r cfbd4eecb941 -r 99fa4fe6b980 vm/src/main/java/org/apidesign/vm4brwsr/VM.java
--- a/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Fri Feb 01 18:42:07 2013 +0100
+++ b/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Tue Feb 05 13:19:06 2013 +0100
@@ -31,8 +31,12 @@
     
     static {
         // uses VMLazy to load dynamic classes
-        VMLazy.init();
-        Zips.init();
+        boolean assertsOn = false;
+        assert assertsOn = true;
+        if (assertsOn) {
+            VMLazy.init();
+            Zips.init();
+        }
     }
 
     @Override