--- old/src/hotspot/share/gc/shared/genCollectedHeap.hpp	2017-10-18 14:02:31.871429492 +0200
+++ new/src/hotspot/share/gc/shared/genCollectedHeap.hpp	2017-10-18 14:02:31.408428360 +0200
@@ -161,10 +161,10 @@
   // The generational collector policy.
   GenCollectorPolicy* gen_policy() const { return _gen_policy; }
 
-  CollectorPolicy* collector_policy() const { return gen_policy(); }
+  virtual CollectorPolicy* collector_policy() const { return gen_policy(); }
 
   // Adaptive size policy
-  AdaptiveSizePolicy* size_policy() {
+  virtual AdaptiveSizePolicy* size_policy() {
     return gen_policy()->size_policy();
   }
 
@@ -217,7 +217,7 @@
   bool is_in_partial_collection(const void* p);
 #endif
 
-  bool is_scavengable(oop obj) {
+  virtual bool is_scavengable(oop obj) {
     return is_in_young(obj);
   }
 
@@ -245,32 +245,32 @@
   // address "addr".  We say "blocks" instead of "object" since some heaps
   // may not pack objects densely; a chunk may either be an object or a
   // non-object.
-  HeapWord* block_start(const void* addr) const;
+  virtual HeapWord* block_start(const void* addr) const;
 
   // Requires "addr" to be the start of a chunk, and returns its size.
   // "addr + size" is required to be the start of a new chunk, or the end
   // of the active area of the heap. Assumes (and verifies in non-product
   // builds) that addr is in the allocated part of the heap and is
   // the start of a chunk.
-  size_t block_size(const HeapWord* addr) const;
+  virtual size_t block_size(const HeapWord* addr) const;
 
   // Requires "addr" to be the start of a block, and returns "TRUE" iff
   // the block is an object. Assumes (and verifies in non-product
   // builds) that addr is in the allocated part of the heap and is
   // the start of a chunk.
-  bool block_is_obj(const HeapWord* addr) const;
+  virtual bool block_is_obj(const HeapWord* addr) const;
 
   // Section on TLAB's.
-  bool supports_tlab_allocation() const;
-  size_t tlab_capacity(Thread* thr) const;
-  size_t tlab_used(Thread* thr) const;
-  size_t unsafe_max_tlab_alloc(Thread* thr) const;
-  HeapWord* allocate_new_tlab(size_t size);
+  virtual bool supports_tlab_allocation() const;
+  virtual size_t tlab_capacity(Thread* thr) const;
+  virtual size_t tlab_used(Thread* thr) const;
+  virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
+  virtual HeapWord* allocate_new_tlab(size_t size);
 
   // Can a compiler initialize a new object without store barriers?
   // This permission only extends from the creation of a new object
   // via a TLAB up to the first subsequent safepoint.
-  bool can_elide_tlab_store_barriers() const {
+  virtual bool can_elide_tlab_store_barriers() const {
     return true;
   }
 
@@ -279,7 +279,7 @@
   // objects therein. This applies to DefNew+Tenured and ParNew+CMS
   // only and may need to be re-examined in case other
   // kinds of collectors are implemented in the future.
-  bool can_elide_initializing_store_barrier(oop new_obj) {
+  virtual bool can_elide_initializing_store_barrier(oop new_obj) {
     return is_in_young(new_obj);
   }
 
@@ -295,11 +295,11 @@
   void release_scratch();
 
   // Ensure parsability: override
-  void ensure_parsability(bool retire_tlabs);
+  virtual void ensure_parsability(bool retire_tlabs);
 
   // Time in ms since the longest time a collector ran in
   // in any generation.
-  jlong millis_since_last_gc();
+  virtual jlong millis_since_last_gc();
 
   // Total number of full collections completed.
   unsigned int total_full_collections_completed() {
@@ -333,10 +333,10 @@
   void verify(VerifyOption option);
 
   // Override.
-  void print_on(outputStream* st) const;
+  virtual void print_on(outputStream* st) const;
   virtual void print_gc_threads_on(outputStream* st) const;
   virtual void gc_threads_do(ThreadClosure* tc) const;
-  void print_tracing_info() const;
+  virtual void print_tracing_info() const;
 
   void print_heap_change(size_t young_prev_used, size_t old_prev_used) const;
 
@@ -356,7 +356,7 @@
   // Return "true" if all generations have reached the
   // maximal committed limit that they can reach, without a garbage
   // collection.
-  bool is_maximal_no_gc() const;
+  virtual bool is_maximal_no_gc() const;
 
   // This function returns the CardTableRS object that allows us to scan
   // generations in a fully generational heap.