--- a/hotspot/src/share/vm/oops/instanceKlassKlass.cpp	Sun Mar 25 18:08:52 2012 -0400
+++ b/hotspot/src/share/vm/oops/instanceKlassKlass.cpp	Thu Mar 29 22:18:56 2012 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -111,7 +111,7 @@
   MarkSweep::mark_and_push(ik->adr_methods_parameter_annotations());
   MarkSweep::mark_and_push(ik->adr_methods_default_annotations());
 
-  // We do not follow adr_implementors() here. It is followed later
+  // We do not follow adr_implementor() here. It is followed later
   // in instanceKlass::follow_weak_klass_links()
 
   klassKlass::oop_follow_contents(obj);
@@ -180,8 +180,8 @@
   blk->do_oop(ik->adr_host_klass());
   blk->do_oop(ik->adr_signers());
   blk->do_oop(ik->adr_inner_classes());
-  for (int i = 0; i < instanceKlass::implementors_limit; i++) {
-    blk->do_oop(&ik->adr_implementors()[i]);
+  if (ik->is_interface()) {
+    blk->do_oop(ik->adr_implementor());
   }
   blk->do_oop(ik->adr_class_annotations());
   blk->do_oop(ik->adr_fields_annotations());
@@ -232,9 +232,9 @@
   if (mr.contains(adr)) blk->do_oop(adr);
   adr = ik->adr_inner_classes();
   if (mr.contains(adr)) blk->do_oop(adr);
-  adr = ik->adr_implementors();
-  for (int i = 0; i < instanceKlass::implementors_limit; i++) {
-    if (mr.contains(&adr[i])) blk->do_oop(&adr[i]);
+  if (ik->is_interface()) {
+    adr = ik->adr_implementor();
+    if (mr.contains(adr)) blk->do_oop(adr);
   }
   adr = ik->adr_class_annotations();
   if (mr.contains(adr)) blk->do_oop(adr);
@@ -273,8 +273,8 @@
   MarkSweep::adjust_pointer(ik->adr_host_klass());
   MarkSweep::adjust_pointer(ik->adr_signers());
   MarkSweep::adjust_pointer(ik->adr_inner_classes());
-  for (int i = 0; i < instanceKlass::implementors_limit; i++) {
-    MarkSweep::adjust_pointer(&ik->adr_implementors()[i]);
+  if (ik->is_interface()) {
+    MarkSweep::adjust_pointer(ik->adr_implementor());
   }
   MarkSweep::adjust_pointer(ik->adr_class_annotations());
   MarkSweep::adjust_pointer(ik->adr_fields_annotations());
@@ -328,6 +328,9 @@
   for (oop* cur_oop = beg_oop; cur_oop < end_oop; ++cur_oop) {
     PSParallelCompact::adjust_pointer(cur_oop);
   }
+  if (ik->is_interface()) {
+    PSParallelCompact::adjust_pointer(ik->adr_implementor());
+  }
 
   OopClosure* closure = PSParallelCompact::adjust_root_pointer_closure();
   iterate_c_heap_oops(ik, closure);
@@ -342,11 +345,18 @@
 instanceKlassKlass::allocate_instance_klass(Symbol* name, int vtable_len, int itable_len,
                                             int static_field_size,
                                             unsigned nonstatic_oop_map_count,
+                                            AccessFlags access_flags,
                                             ReferenceType rt, TRAPS) {
 
   const int nonstatic_oop_map_size =
     instanceKlass::nonstatic_oop_map_size(nonstatic_oop_map_count);
-  int size = instanceKlass::object_size(align_object_offset(vtable_len) + align_object_offset(itable_len) + nonstatic_oop_map_size);
+  int size = align_object_offset(vtable_len) + align_object_offset(itable_len);
+  if (access_flags.is_interface()) {
+    size += align_object_offset(nonstatic_oop_map_size) + (int)sizeof(klassOop)/HeapWordSize;
+  } else {
+    size += nonstatic_oop_map_size;
+  }
+  size = instanceKlass::object_size(size);
 
   // Allocation
   KlassHandle h_this_klass(THREAD, as_klassOop());
@@ -378,6 +388,7 @@
     ik->set_itable_length(itable_len);
     ik->set_static_field_size(static_field_size);
     ik->set_nonstatic_oop_map_size(nonstatic_oop_map_size);
+    ik->set_access_flags(access_flags);
     assert(k()->size() == size, "wrong size for object");
 
     ik->set_array_klasses(NULL);
@@ -470,16 +481,12 @@
 
   if (ik->is_interface()) {
     st->print_cr(BULLET"nof implementors:  %d", ik->nof_implementors());
-    int print_impl = 0;
-    for (int i = 0; i < instanceKlass::implementors_limit; i++) {
-      if (ik->implementor(i) != NULL) {
-        if (++print_impl == 1)
-          st->print_cr(BULLET"implementor:    ");
-        st->print("   ");
-        ik->implementor(i)->print_value_on(st);
-      }
+    if (ik->nof_implementors() == 1) {
+      st->print_cr(BULLET"implementor:    ");
+      st->print("   ");
+      ik->implementor()->print_value_on(st);
+      st->cr();
     }
-    if (print_impl > 0)  st->cr();
   }
 
   st->print(BULLET"arrays:            "); ik->array_klasses()->print_value_on(st);     st->cr();
@@ -640,16 +647,12 @@
     }
 
     // Verify implementor fields
-    bool saw_null_impl = false;
-    for (int i = 0; i < instanceKlass::implementors_limit; i++) {
-      klassOop im = ik->implementor(i);
-      if (im == NULL) { saw_null_impl = true; continue; }
-      guarantee(!saw_null_impl, "non-nulls must preceded all nulls");
+    klassOop im = ik->implementor();
+    if (im != NULL) {
       guarantee(ik->is_interface(), "only interfaces should have implementor set");
-      guarantee(i < ik->nof_implementors(), "should only have one implementor");
       guarantee(im->is_perm(),  "should be in permspace");
       guarantee(im->is_klass(), "should be klass");
-      guarantee(!Klass::cast(klassOop(im))->is_interface(), "implementors cannot be interfaces");
+      guarantee(!Klass::cast(klassOop(im))->is_interface() || im == ik->as_klassOop(), "implementors cannot be interfaces");
     }
 
     // Verify local interfaces