diff -r 5818d9cfb2e7 -r 644b62cf678f src/HOL/MicroJava/J/Example.thy
--- a/src/HOL/MicroJava/J/Example.thy	Tue Oct 07 16:07:40 2008 +0200
+++ b/src/HOL/MicroJava/J/Example.thy	Tue Oct 07 16:07:50 2008 +0200
@@ -137,7 +137,7 @@
 done
 declare map_of_Cons [simp del] -- "sic!"
 
-lemma class_tprg_Object [simp]: "class tprg Object = Some (arbitrary, [], [])"
+lemma class_tprg_Object [simp]: "class tprg Object = Some (undefined, [], [])"
 apply (unfold ObjectC_def class_def)
 apply (simp (no_asm))
 done