--- old/src/share/vm/gc/shared/generation.cpp	2015-09-09 13:49:15.000000000 +0200
+++ new/src/share/vm/gc/shared/generation.cpp	2015-09-09 13:49:15.000000000 +0200
@@ -58,12 +58,12 @@
           (HeapWord*)_virtual_space.high_boundary());
 }
 
-GenerationSpec* Generation::spec() {
+size_t Generation::initial_size() {
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   if (gch->is_young_gen(this)) {
-    return gch->gen_policy()->young_gen_spec();
+    return gch->gen_policy()->young_gen_spec()->init_size();
   }
-  return gch->gen_policy()->old_gen_spec();
+  return gch->gen_policy()->old_gen_spec()->init_size();
 }
 
 size_t Generation::max_capacity() const {