--- a/src/share/vm/prims/jvm.cpp	Fri May 31 10:27:12 2013 +0100
+++ b/src/share/vm/prims/jvm.cpp	Mon Jun 17 11:17:49 2013 +0100
@@ -1072,11 +1072,7 @@
     return NULL;
   }
 
-  Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(cls));
-  objArrayOop signers = NULL;
-  if (k->oop_is_instance()) {
-    signers = InstanceKlass::cast(k)->signers();
-  }
+  objArrayOop signers = java_lang_Class::signers(JNIHandles::resolve_non_null(cls));
 
   // If there are no signers set in the class, or if the class
   // is an array, return NULL.
@@ -1102,7 +1098,7 @@
     // be called with an array.  Only the bootstrap loader creates arrays.
     Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(cls));
     if (k->oop_is_instance()) {
-      InstanceKlass::cast(k)->set_signers(objArrayOop(JNIHandles::resolve(signers)));
+      java_lang_Class::set_signers(k->java_mirror(), objArrayOop(JNIHandles::resolve(signers)));
     }
   }
 JVM_END
@@ -1119,8 +1115,8 @@
     return NULL;
   }
 
-  Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve(cls));
-  return (jobject) JNIHandles::make_local(env, k->protection_domain());
+  oop pd = java_lang_Class::protection_domain(JNIHandles::resolve(cls));
+  return (jobject) JNIHandles::make_local(env, pd);
 JVM_END
 
 
@@ -1139,7 +1135,7 @@
     if (k->oop_is_instance()) {
       oop pd = JNIHandles::resolve(protection_domain);
       assert(pd == NULL || pd->is_oop(), "just checking");
-      InstanceKlass::cast(k)->set_protection_domain(pd);
+      java_lang_Class::set_protection_domain(k->java_mirror(), pd);
     }
   }
 JVM_END