--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsCollectorPolicy.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsCollectorPolicy.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -52,21 +52,9 @@
 }
 
 void ConcurrentMarkSweepPolicy::initialize_generations() {
-  _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC,
-    CURRENT_PC, AllocFailStrategy::RETURN_NULL);
-  if (_generations == NULL)
-    vm_exit_during_initialization("Unable to allocate gen spec");
-
-  Generation::Name yg_name =
-    UseParNewGC ? Generation::ParNew : Generation::DefNew;
-  _generations[0] = new GenerationSpec(yg_name, _initial_young_size,
-                                       _max_young_size);
-  _generations[1] = new GenerationSpec(Generation::ConcurrentMarkSweep,
-                                       _initial_old_size, _max_old_size);
-
-  if (_generations[0] == NULL || _generations[1] == NULL) {
-    vm_exit_during_initialization("Unable to allocate gen spec");
-  }
+  _generations = NEW_C_HEAP_ARRAY(GenerationSpecPtr, number_of_generations(), mtGC);
+  _generations[0] = new GenerationSpec(Generation::ParNew, _initial_young_size, _max_young_size);
+  _generations[1] = new GenerationSpec(Generation::ConcurrentMarkSweep, _initial_old_size, _max_old_size);
 }
 
 void ConcurrentMarkSweepPolicy::initialize_size_policy(size_t init_eden_size,
@@ -82,10 +70,5 @@
 
 void ConcurrentMarkSweepPolicy::initialize_gc_policy_counters() {
   // initialize the policy counters - 2 collectors, 3 generations
-  if (UseParNewGC) {
-    _gc_policy_counters = new GCPolicyCounters("ParNew:CMS", 2, 3);
-  }
-  else {
-    _gc_policy_counters = new GCPolicyCounters("Copy:CMS", 2, 3);
-  }
+  _gc_policy_counters = new GCPolicyCounters("ParNew:CMS", 2, 3);
 }

--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -4094,10 +4094,7 @@
   }
 
   if (clean_survivor) {  // preclean the active survivor space(s)
-    assert(_young_gen->kind() == Generation::DefNew ||
-           _young_gen->kind() == Generation::ParNew,
-         "incorrect type for cast");
-    DefNewGeneration* dng = (DefNewGeneration*)_young_gen;
+    DefNewGeneration* dng = _young_gen->as_DefNewGeneration();
     PushAndMarkClosure pam_cl(this, _span, ref_processor(),
                              &_markBitMap, &_modUnionTable,
                              &_markStack, true /* precleaning phase */);
@@ -5168,7 +5165,7 @@
 CMSCollector::
 initialize_sequential_subtasks_for_young_gen_rescan(int n_threads) {
   assert(n_threads > 0, "Unexpected n_threads argument");
-  DefNewGeneration* dng = (DefNewGeneration*)_young_gen;
+  DefNewGeneration* dng = _young_gen->as_DefNewGeneration();
 
   // Eden space
   if (!dng->eden()->is_empty()) {

--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -1256,8 +1256,6 @@
   virtual const char* short_name() const { return "CMS"; }
   void        print() const;
   void printOccupancy(const char* s);
-  bool must_be_youngest() const { return false; }
-  bool must_be_oldest()   const { return true; }
 
   // Resize the generation after a compacting GC.  The
   // generation can be treated as a contiguous space

--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -372,7 +372,6 @@
 
   // override
   virtual bool refs_discovery_is_mt()     const {
-    assert(UseParNewGC, "ParNewGeneration only when UseParNewGC");
     return ParallelGCThreads > 1;
   }
 

--- a/hotspot/src/share/vm/memory/cardTableRS.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/cardTableRS.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -283,14 +283,14 @@
   // Convert the assertion check to a warning if we are running
   // CMS+ParNew until related bug is fixed.
   MemRegion ur    = sp->used_region();
-  assert(ur.contains(urasm) || (UseConcMarkSweepGC && UseParNewGC),
+  assert(ur.contains(urasm) || (UseConcMarkSweepGC),
          err_msg("Did you forget to call save_marks()? "
                  "[" PTR_FORMAT ", " PTR_FORMAT ") is not contained in "
                  "[" PTR_FORMAT ", " PTR_FORMAT ")",
                  p2i(urasm.start()), p2i(urasm.end()), p2i(ur.start()), p2i(ur.end())));
   // In the case of CMS+ParNew, issue a warning
   if (!ur.contains(urasm)) {
-    assert(UseConcMarkSweepGC && UseParNewGC, "Tautology: see assert above");
+    assert(UseConcMarkSweepGC, "Tautology: see assert above");
     warning("CMS+ParNew: Did you forget to call save_marks()? "
             "[" PTR_FORMAT ", " PTR_FORMAT ") is not contained in "
             "[" PTR_FORMAT ", " PTR_FORMAT ")",
@@ -609,21 +609,3 @@
     _ct_bs->verify();
     }
   }
-
-
-void CardTableRS::verify_aligned_region_empty(MemRegion mr) {
-  if (!mr.is_empty()) {
-    jbyte* cur_entry = byte_for(mr.start());
-    jbyte* limit = byte_after(mr.last());
-    // The region mr may not start on a card boundary so
-    // the first card may reflect a write to the space
-    // just prior to mr.
-    if (!is_aligned(mr.start())) {
-      cur_entry++;
-    }
-    for (;cur_entry < limit; cur_entry++) {
-      guarantee(*cur_entry == CardTableModRefBS::clean_card,
-                "Unexpected dirty card found");
-    }
-  }
-}

--- a/hotspot/src/share/vm/memory/cardTableRS.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/cardTableRS.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -138,7 +138,6 @@
   }
 
   void verify();
-  void verify_aligned_region_empty(MemRegion mr);
 
   void clear(MemRegion mr) { _ct_bs->clear(mr); }
   void clear_into_younger(Generation* old_gen);

--- a/hotspot/src/share/vm/memory/collectorPolicy.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/collectorPolicy.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -908,31 +908,14 @@
 }
 
 void MarkSweepPolicy::initialize_generations() {
-  _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, CURRENT_PC,
-    AllocFailStrategy::RETURN_NULL);
-  if (_generations == NULL) {
-    vm_exit_during_initialization("Unable to allocate gen spec");
-  }
-
-  if (UseParNewGC) {
-    _generations[0] = new GenerationSpec(Generation::ParNew, _initial_young_size, _max_young_size);
-  } else {
-    _generations[0] = new GenerationSpec(Generation::DefNew, _initial_young_size, _max_young_size);
-  }
+  _generations = NEW_C_HEAP_ARRAY(GenerationSpecPtr, number_of_generations(), mtGC);
+  _generations[0] = new GenerationSpec(Generation::DefNew, _initial_young_size, _max_young_size);
   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_old_size, _max_old_size);
-
-  if (_generations[0] == NULL || _generations[1] == NULL) {
-    vm_exit_during_initialization("Unable to allocate gen spec");
-  }
 }
 
 void MarkSweepPolicy::initialize_gc_policy_counters() {
   // Initialize the policy counters - 2 collectors, 3 generations.
-  if (UseParNewGC) {
-    _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);
-  } else {
-    _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
-  }
+  _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
 }
 
 /////////////// Unit tests ///////////////

--- a/hotspot/src/share/vm/memory/defNewGeneration.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/defNewGeneration.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -340,9 +340,6 @@
   virtual const char* name() const;
   virtual const char* short_name() const { return "DefNew"; }
 
-  bool must_be_youngest() const { return true; }
-  bool must_be_oldest() const { return false; }
-
   // PrintHeapAtGC support.
   void print_on(outputStream* st) const;
 

--- a/hotspot/src/share/vm/memory/genCollectedHeap.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -182,10 +182,7 @@
   SharedHeap::post_initialize();
   GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
   guarantee(policy->is_generation_policy(), "Illegal policy type");
-  DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
-  assert(def_new_gen->kind() == Generation::DefNew ||
-         def_new_gen->kind() == Generation::ParNew,
-         "Wrong generation kind");
+  DefNewGeneration* def_new_gen = get_gen(0)->as_DefNewGeneration();
 
   Generation* old_gen = get_gen(1);
   assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
@@ -1117,10 +1114,8 @@
 
 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
 #if INCLUDE_ALL_GCS
-  if (UseParNewGC) {
+  if (UseConcMarkSweepGC) {
     workers()->print_worker_threads_on(st);
-  }
-  if (UseConcMarkSweepGC) {
     ConcurrentMarkSweepThread::print_all_on(st);
   }
 #endif // INCLUDE_ALL_GCS

--- a/hotspot/src/share/vm/memory/genCollectedHeap.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -262,12 +262,12 @@
 
   // We don't need barriers for stores to objects in the
   // young gen and, a fortiori, for initializing stores to
-  // objects therein. This applies to {DefNew,ParNew}+{Tenured,CMS}
+  // 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.
   virtual bool can_elide_initializing_store_barrier(oop new_obj) {
     // We wanted to assert that:-
-    // assert(UseParNewGC || UseSerialGC || UseConcMarkSweepGC,
+    // assert(UseSerialGC || UseConcMarkSweepGC,
     //       "Check can_elide_initializing_store_barrier() for this collector");
     // but unfortunately the flag UseSerialGC need not necessarily always
     // be set when DefNew+Tenured are being used.

--- a/hotspot/src/share/vm/memory/genRemSet.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/genRemSet.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -105,17 +105,6 @@
 
   virtual void verify() = 0;
 
-  // Verify that the remembered set has no entries for
-  // the heap interval denoted by mr.  If there are any
-  // alignment constraints on the remembered set, only the
-  // part of the region that is aligned is checked.
-  //
-  //   alignment boundaries
-  //   +--------+-------+--------+-------+
-  //         [ region mr              )
-  //            [ part checked   )
-  virtual void verify_aligned_region_empty(MemRegion mr) = 0;
-
   // If appropriate, print some information about the remset on "tty".
   virtual void print() {}
 

--- a/hotspot/src/share/vm/memory/generation.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/generation.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -517,13 +517,6 @@
 
   int level() const { return _level; }
 
-  // Attributes
-
-  // True iff the given generation may only be the youngest generation.
-  virtual bool must_be_youngest() const = 0;
-  // True iff the given generation may only be the oldest generation.
-  virtual bool must_be_oldest() const = 0;
-
   // Reference Processing accessor
   ReferenceProcessor* const ref_processor() { return _ref_processor; }
 

--- a/hotspot/src/share/vm/memory/sharedHeap.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/sharedHeap.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -68,9 +68,7 @@
     vm_exit_during_initialization("Failed necessary allocation.");
   }
   _sh = this;  // ch is static, should be set only once.
-  if (UseParNewGC ||
-      UseG1GC ||
-      (UseConcMarkSweepGC && (CMSParallelInitialMarkEnabled || CMSParallelRemarkEnabled) && use_parallel_gc_threads())) {
+  if (UseConcMarkSweepGC || UseG1GC) {
     _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,
                             /* are_GC_task_threads */true,
                             /* are_ConcurrentGC_threads */false);

--- a/hotspot/src/share/vm/memory/tenuredGeneration.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/tenuredGeneration.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -64,46 +64,13 @@
   _space_counters = new CSpaceCounters(gen_name, 0,
                                        _virtual_space.reserved_size(),
                                        _the_space, _gen_counters);
-#if INCLUDE_ALL_GCS
-  if (UseParNewGC) {
-    typedef ParGCAllocBufferWithBOT* ParGCAllocBufferWithBOTPtr;
-    _alloc_buffers = NEW_C_HEAP_ARRAY(ParGCAllocBufferWithBOTPtr,
-                                      ParallelGCThreads, mtGC);
-    if (_alloc_buffers == NULL)
-      vm_exit_during_initialization("Could not allocate alloc_buffers");
-    for (uint i = 0; i < ParallelGCThreads; i++) {
-      _alloc_buffers[i] =
-        new ParGCAllocBufferWithBOT(OldPLABSize, _bts);
-      if (_alloc_buffers[i] == NULL)
-        vm_exit_during_initialization("Could not allocate alloc_buffers");
-    }
-  } else {
-    _alloc_buffers = NULL;
-  }
-#endif // INCLUDE_ALL_GCS
-}
-
-
-const char* TenuredGeneration::name() const {
-  return "tenured generation";
 }
 
 void TenuredGeneration::gc_prologue(bool full) {
   _capacity_at_prologue = capacity();
   _used_at_prologue = used();
-  if (VerifyBeforeGC) {
-    verify_alloc_buffers_clean();
-  }
 }
 
-void TenuredGeneration::gc_epilogue(bool full) {
-  if (VerifyAfterGC) {
-    verify_alloc_buffers_clean();
-  }
-  OneContigSpaceCardGeneration::gc_epilogue(full);
-}
-
-
 bool TenuredGeneration::should_collect(bool  full,
                                        size_t size,
                                        bool   is_tlab) {
@@ -149,15 +116,6 @@
   return result;
 }
 
-void TenuredGeneration::collect(bool   full,
-                                bool   clear_all_soft_refs,
-                                size_t size,
-                                bool   is_tlab) {
-  retire_alloc_buffers_before_full_gc();
-  OneContigSpaceCardGeneration::collect(full, clear_all_soft_refs,
-                                        size, is_tlab);
-}
-
 void TenuredGeneration::compute_new_size() {
   assert_locked_or_safepoint(Heap_lock);
 
@@ -171,6 +129,7 @@
          err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT
          " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity()));
 }
+
 void TenuredGeneration::update_gc_stats(int current_level,
                                         bool full) {
   // If the next lower level(s) has been collected, gather any statistics
@@ -198,96 +157,6 @@
   }
 }
 
-
-#if INCLUDE_ALL_GCS
-oop TenuredGeneration::par_promote(int thread_num,
-                                   oop old, markOop m, size_t word_sz) {
-
-  ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
-  HeapWord* obj_ptr = buf->allocate(word_sz);
-  bool is_lab = true;
-  if (obj_ptr == NULL) {
-#ifndef PRODUCT
-    if (Universe::heap()->promotion_should_fail()) {
-      return NULL;
-    }
-#endif  // #ifndef PRODUCT
-
-    // Slow path:
-    if (word_sz * 100 < ParallelGCBufferWastePct * buf->word_sz()) {
-      // Is small enough; abandon this buffer and start a new one.
-      size_t buf_size = buf->word_sz();
-      HeapWord* buf_space =
-        TenuredGeneration::par_allocate(buf_size, false);
-      if (buf_space == NULL) {
-        buf_space = expand_and_allocate(buf_size, false, true /* parallel*/);
-      }
-      if (buf_space != NULL) {
-        buf->retire(false, false);
-        buf->set_buf(buf_space);
-        obj_ptr = buf->allocate(word_sz);
-        assert(obj_ptr != NULL, "Buffer was definitely big enough...");
-      }
-    };
-    // Otherwise, buffer allocation failed; try allocating object
-    // individually.
-    if (obj_ptr == NULL) {
-      obj_ptr = TenuredGeneration::par_allocate(word_sz, false);
-      if (obj_ptr == NULL) {
-        obj_ptr = expand_and_allocate(word_sz, false, true /* parallel */);
-      }
-    }
-    if (obj_ptr == NULL) return NULL;
-  }
-  assert(obj_ptr != NULL, "program logic");
-  Copy::aligned_disjoint_words((HeapWord*)old, obj_ptr, word_sz);
-  oop obj = oop(obj_ptr);
-  // Restore the mark word copied above.
-  obj->set_mark(m);
-  return obj;
-}
-
-void TenuredGeneration::par_promote_alloc_undo(int thread_num,
-                                               HeapWord* obj,
-                                               size_t word_sz) {
-  ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
-  if (buf->contains(obj)) {
-    guarantee(buf->contains(obj + word_sz - 1),
-              "should contain whole object");
-    buf->undo_allocation(obj, word_sz);
-  } else {
-    CollectedHeap::fill_with_object(obj, word_sz);
-  }
-}
-
-void TenuredGeneration::par_promote_alloc_done(int thread_num) {
-  ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
-  buf->retire(true, ParallelGCRetainPLAB);
-}
-
-void TenuredGeneration::retire_alloc_buffers_before_full_gc() {
-  if (UseParNewGC) {
-    for (uint i = 0; i < ParallelGCThreads; i++) {
-      _alloc_buffers[i]->retire(true /*end_of_gc*/, false /*retain*/);
-    }
-  }
-}
-
-// Verify that any retained parallel allocation buffers do not
-// intersect with dirty cards.
-void TenuredGeneration::verify_alloc_buffers_clean() {
-  if (UseParNewGC) {
-    for (uint i = 0; i < ParallelGCThreads; i++) {
-      _rs->verify_aligned_region_empty(_alloc_buffers[i]->range());
-    }
-  }
-}
-
-#else  // INCLUDE_ALL_GCS
-void TenuredGeneration::retire_alloc_buffers_before_full_gc() {}
-void TenuredGeneration::verify_alloc_buffers_clean() {}
-#endif // INCLUDE_ALL_GCS
-
 bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
   size_t available = max_contiguous_available();
   size_t av_promo  = (size_t)gc_stats()->avg_promoted()->padded_average();

--- a/hotspot/src/share/vm/memory/tenuredGeneration.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/memory/tenuredGeneration.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -33,22 +33,9 @@
 
 // TenuredGeneration models the heap containing old (promoted/tenured) objects.
 
-class ParGCAllocBufferWithBOT;
-
 class TenuredGeneration: public OneContigSpaceCardGeneration {
   friend class VMStructs;
  protected:
-
-#if INCLUDE_ALL_GCS
-  // To support parallel promotion: an array of parallel allocation
-  // buffers, one per thread, initially NULL.
-  ParGCAllocBufferWithBOT** _alloc_buffers;
-#endif // INCLUDE_ALL_GCS
-
-  // Retire all alloc buffers before a full GC, so that they will be
-  // re-allocated at the start of the next young GC.
-  void retire_alloc_buffers_before_full_gc();
-
   GenerationCounters*   _gen_counters;
   CSpaceCounters*       _space_counters;
 
@@ -59,10 +46,8 @@
   Generation::Name kind() { return Generation::MarkSweepCompact; }
 
   // Printing
-  const char* name() const;
+  const char* name() const { return "tenured generation"; }
   const char* short_name() const { return "Tenured"; }
-  bool must_be_youngest() const { return false; }
-  bool must_be_oldest() const { return true; }
 
   // Does a "full" (forced) collection invoked on this generation collect
   // all younger generations as well? Note that this is a
@@ -73,26 +58,12 @@
   }
 
   virtual void gc_prologue(bool full);
-  virtual void gc_epilogue(bool full);
   bool should_collect(bool   full,
                       size_t word_size,
                       bool   is_tlab);
 
-  virtual void collect(bool full,
-                       bool clear_all_soft_refs,
-                       size_t size,
-                       bool is_tlab);
   virtual void compute_new_size();
 
-#if INCLUDE_ALL_GCS
-  // Overrides.
-  virtual oop par_promote(int thread_num,
-                          oop obj, markOop m, size_t word_sz);
-  virtual void par_promote_alloc_undo(int thread_num,
-                                      HeapWord* obj, size_t word_sz);
-  virtual void par_promote_alloc_done(int thread_num);
-#endif // INCLUDE_ALL_GCS
-
   // Performance Counter support
   void update_counters();
 
@@ -101,8 +72,6 @@
   virtual void update_gc_stats(int level, bool full);
 
   virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;
-
-  void verify_alloc_buffers_clean();
 };
 
 #endif // SHARE_VM_MEMORY_TENUREDGENERATION_HPP

--- a/hotspot/src/share/vm/oops/oop.inline.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/oops/oop.inline.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -441,12 +441,12 @@
       s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
         HeapWordSize);
 
-      // UseParNewGC, UseParallelGC and UseG1GC can change the length field
+      // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
       // of an "old copy" of an object array in the young gen so it indicates
       // the grey portion of an already copied array. This will cause the first
       // disjunct below to fail if the two comparands are computed across such
       // a concurrent change.
-      // UseParNewGC also runs with promotion labs (which look like int
+      // ParNew also runs with promotion labs (which look like int
       // filler arrays) which are subject to changing their declared size
       // when finally retiring a PLAB; this also can cause the first disjunct
       // to fail for another worker thread that is concurrently walking the block
@@ -458,8 +458,8 @@
       // technique, we will need to suitably modify the assertion.
       assert((s == klass->oop_size(this)) ||
              (Universe::heap()->is_gc_active() &&
-              ((is_typeArray() && UseParNewGC) ||
-               (is_objArray()  && is_forwarded() && (UseParNewGC || UseParallelGC || UseG1GC)))),
+              ((is_typeArray() && UseConcMarkSweepGC) ||
+               (is_objArray()  && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
              "wrong array object size");
     } else {
       // Must be zero, so bite the bullet and take the virtual call.

--- a/hotspot/src/share/vm/runtime/arguments.cpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/runtime/arguments.cpp	Thu Nov 27 21:02:13 2014 +0100
@@ -1260,10 +1260,8 @@
 void Arguments::set_parnew_gc_flags() {
   assert(!UseSerialGC && !UseParallelOldGC && !UseParallelGC && !UseG1GC,
          "control point invariant");
-  assert(UseParNewGC, "Error");
-
-  // Turn off AdaptiveSizePolicy for parnew until it is complete.
-  disable_adaptive_size_policy("UseParNewGC");
+  assert(UseConcMarkSweepGC, "CMS is expected to be on here");
+  assert(UseParNewGC, "ParNew should always be used with CMS");
 
   if (FLAG_IS_DEFAULT(ParallelGCThreads)) {
     FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::parallel_worker_threads());
@@ -1304,21 +1302,12 @@
 void Arguments::set_cms_and_parnew_gc_flags() {
   assert(!UseSerialGC && !UseParallelOldGC && !UseParallelGC, "Error");
   assert(UseConcMarkSweepGC, "CMS is expected to be on here");
-
-  // If we are using CMS, we prefer to UseParNewGC,
-  // unless explicitly forbidden.
-  if (FLAG_IS_DEFAULT(UseParNewGC)) {
-    FLAG_SET_ERGO(bool, UseParNewGC, true);
-  }
+  assert(UseParNewGC, "ParNew should always be used with CMS");
 
   // Turn off AdaptiveSizePolicy by default for cms until it is complete.
   disable_adaptive_size_policy("UseConcMarkSweepGC");
 
-  // In either case, adjust ParallelGCThreads and/or UseParNewGC
-  // as needed.
-  if (UseParNewGC) {
-    set_parnew_gc_flags();
-  }
+  set_parnew_gc_flags();
 
   size_t max_heap = align_size_down(MaxHeapSize,
                                     CardTableRS::ct_max_alignment_constraint());
@@ -1788,14 +1777,11 @@
   // Set per-collector flags
   if (UseParallelGC || UseParallelOldGC) {
     set_parallel_gc_flags();
-  } else if (UseConcMarkSweepGC) { // Should be done before ParNew check below
+  } else if (UseConcMarkSweepGC) {
     set_cms_and_parnew_gc_flags();
-  } else if (UseParNewGC) {  // Skipped if CMS is set above
-    set_parnew_gc_flags();
   } else if (UseG1GC) {
     set_g1_gc_flags();
   }
-  check_deprecated_gcs();
   check_deprecated_gc_flags();
   if (AssumeMP && !UseSerialGC) {
     if (FLAG_IS_DEFAULT(ParallelGCThreads) && ParallelGCThreads == 1) {
@@ -2156,17 +2142,11 @@
 // Check consistency of GC selection
 bool Arguments::check_gc_consistency_user() {
   check_gclog_consistency();
-  bool status = true;
   // Ensure that the user has not selected conflicting sets
-  // of collectors. [Note: this check is merely a user convenience;
-  // collectors over-ride each other so that only a non-conflicting
-  // set is selected; however what the user gets is not what they
-  // may have expected from the combination they asked for. It's
-  // better to reduce user confusion by not allowing them to
-  // select conflicting combinations.
+  // of collectors.
   uint i = 0;
   if (UseSerialGC)                       i++;
-  if (UseConcMarkSweepGC || UseParNewGC) i++;
+  if (UseConcMarkSweepGC)                i++;
   if (UseParallelGC || UseParallelOldGC) i++;
   if (UseG1GC)                           i++;
   if (i > 1) {
@@ -2174,26 +2154,30 @@
                 "Conflicting collector combinations in option list; "
                 "please refer to the release notes for the combinations "
                 "allowed\n");
-    status = false;
+    return false;
   }
-  return status;
-}
-
-void Arguments::check_deprecated_gcs() {
+
   if (UseConcMarkSweepGC && !UseParNewGC) {
-    warning("Using the DefNew young collector with the CMS collector is deprecated "
-        "and will likely be removed in a future release");
+    jio_fprintf(defaultStream::error_stream(),
+        "It is not possible to combine the DefNew young collector with the CMS collector.\n");
+    return false;
   }
 
   if (UseParNewGC && !UseConcMarkSweepGC) {
     // !UseConcMarkSweepGC means that we are using serial old gc. Unfortunately we don't
     // set up UseSerialGC properly, so that can't be used in the check here.
-    warning("Using the ParNew young collector with the Serial old collector is deprecated "
-        "and will likely be removed in a future release");
+    jio_fprintf(defaultStream::error_stream(),
+        "It is not possible to combine the ParNew young collector with the Serial old collector.\n");
+    return false;
   }
+
+  return true;
 }
 
 void Arguments::check_deprecated_gc_flags() {
+  if (FLAG_IS_CMDLINE(UseParNewGC)) {
+    warning("The UseParNewGC flag is deprecated and will likely be removed in a future release");
+  }
   if (FLAG_IS_CMDLINE(MaxGCMinorPauseMillis)) {
     warning("Using MaxGCMinorPauseMillis as minor pause goal is deprecated"
             "and will likely be removed in future release");
@@ -3556,6 +3540,11 @@
     }
   }
 
+  if (UseConcMarkSweepGC && FLAG_IS_DEFAULT(UseParNewGC) && !UseParNewGC) {
+    // CMS can only be used with ParNew
+    FLAG_SET_ERGO(bool, UseParNewGC, true);
+  }
+
   if (!check_vm_args_consistency()) {
     return JNI_ERR;
   }

--- a/hotspot/src/share/vm/runtime/arguments.hpp	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/src/share/vm/runtime/arguments.hpp	Thu Nov 27 21:02:13 2014 +0100
@@ -472,7 +472,6 @@
   // Check for consistency in the selection of the garbage collector.
   static bool check_gc_consistency_user();        // Check user-selected gc
   static inline bool check_gc_consistency_ergo(); // Check ergonomic-selected gc
-  static void check_deprecated_gcs();
   static void check_deprecated_gc_flags();
   // Check consistency or otherwise of VM argument settings
   static bool check_vm_args_consistency();
@@ -615,8 +614,7 @@
 };
 
 bool Arguments::gc_selected() {
-  return UseConcMarkSweepGC || UseG1GC || UseParallelGC || UseParallelOldGC ||
-    UseParNewGC || UseSerialGC;
+  return UseConcMarkSweepGC || UseG1GC || UseParallelGC || UseParallelOldGC || UseSerialGC;
 }
 
 bool Arguments::check_gc_consistency_ergo() {

--- a/hotspot/test/compiler/8010927/Test8010927.java	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/test/compiler/8010927/Test8010927.java	Thu Nov 27 21:02:13 2014 +0100
@@ -29,7 +29,7 @@
  * @build Test8010927
  * @run main ClassFileInstaller sun.hotspot.WhiteBox
  *                              sun.hotspot.WhiteBox$WhiteBoxPermission
- * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+IgnoreUnrecognizedVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xmx64m -XX:NewSize=20971520 -XX:MaxNewSize=32m -XX:-UseTLAB -XX:-UseParNewGC -XX:-UseAdaptiveSizePolicy Test8010927
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+IgnoreUnrecognizedVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xmx64m -XX:NewSize=20971520 -XX:MaxNewSize=32m -XX:-UseTLAB -XX:-UseAdaptiveSizePolicy Test8010927
  */
 
 import sun.hotspot.WhiteBox;

--- a/hotspot/test/gc/TestSystemGC.java	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/test/gc/TestSystemGC.java	Thu Nov 27 21:02:13 2014 +0100
@@ -28,12 +28,10 @@
  * @summary Runs System.gc() with different flags.
  * @run main/othervm TestSystemGC
  * @run main/othervm -XX:+UseSerialGC TestSystemGC
- * @run main/othervm -XX:+UseParNewGC TestSystemGC
  * @run main/othervm -XX:+UseParallelGC TestSystemGC
  * @run main/othervm -XX:+UseParallelGC -XX:-UseParallelOldGC TestSystemGC
  * @run main/othervm -XX:+UseConcMarkSweepGC TestSystemGC
  * @run main/othervm -XX:+UseConcMarkSweepGC -XX:+ExplicitGCInvokesConcurrent TestSystemGC
- * @run main/othervm -XX:+UseConcMarkSweepGC -XX:+ExplicitGCInvokesConcurrent -XX:-UseParNewGC TestSystemGC
  * @run main/othervm -XX:+UseG1GC TestSystemGC
  * @run main/othervm -XX:+UseG1GC -XX:+ExplicitGCInvokesConcurrent TestSystemGC
  * @run main/othervm -XX:+UseLargePages TestSystemGC

--- a/hotspot/test/gc/startup_warnings/TestDefNewCMS.java	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/test/gc/startup_warnings/TestDefNewCMS.java	Thu Nov 27 21:02:13 2014 +0100
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2013, 2014, 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
@@ -24,8 +24,8 @@
 /*
 * @test TestDefNewCMS
 * @key gc
-* @bug 8006398
-* @summary Test that the deprecated DefNew+CMS combination print a warning message
+* @bug 8065972
+* @summary Test that the unsupported DefNew+CMS combination does not start
 * @library /testlibrary
 */
 
@@ -37,9 +37,9 @@
   public static void main(String args[]) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:-UseParNewGC", "-XX:+UseConcMarkSweepGC", "-version");
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
-    output.shouldContain("warning: Using the DefNew young collector with the CMS collector is deprecated and will likely be removed in a future release");
-    output.shouldNotContain("error");
-    output.shouldHaveExitValue(0);
+    output.shouldContain("It is not possible to combine the DefNew young collector with the CMS collector.");
+    output.shouldContain("Error");
+    output.shouldHaveExitValue(1);
   }
 
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/startup_warnings/TestNoParNew.java	Thu Nov 27 21:02:13 2014 +0100
@@ -0,0 +1,46 @@
+/*
+* Copyright (c) 2014, 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
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+
+/*
+* @test TestNoParNew
+* @key gc
+* @bug 8065972
+* @summary Test that specifying -XX:-UseParNewGC on the command line logs a warning message
+* @library /testlibrary
+*/
+
+import com.oracle.java.testlibrary.OutputAnalyzer;
+import com.oracle.java.testlibrary.ProcessTools;
+
+
+public class TestNoParNew {
+
+  public static void main(String args[]) throws Exception {
+    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:-UseParNewGC", "-version");
+    OutputAnalyzer output = new OutputAnalyzer(pb.start());
+    output.shouldContain("warning: The UseParNewGC flag is deprecated and will likely be removed in a future release");
+    output.shouldNotContain("error");
+    output.shouldHaveExitValue(0);
+  }
+
+}

--- a/hotspot/test/gc/startup_warnings/TestParNewCMS.java	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/test/gc/startup_warnings/TestParNewCMS.java	Thu Nov 27 21:02:13 2014 +0100
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2013, 2014, 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
@@ -24,8 +24,8 @@
 /*
 * @test TestParNewCMS
 * @key gc
-* @bug 8006398
-* @summary Test that the combination ParNew+CMS does not print a warning message
+* @bug 8065972
+* @summary Test that specifying -XX:+UseParNewGC on the command line logs a warning message
 * @library /testlibrary
 */
 
@@ -38,7 +38,7 @@
   public static void main(String args[]) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseParNewGC", "-XX:+UseConcMarkSweepGC", "-version");
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
-    output.shouldNotContain("deprecated");
+    output.shouldContain("warning: The UseParNewGC flag is deprecated and will likely be removed in a future release");
     output.shouldNotContain("error");
     output.shouldHaveExitValue(0);
   }

--- a/hotspot/test/gc/startup_warnings/TestParNewSerialOld.java	Thu Nov 27 11:09:55 2014 +0100
+++ b/hotspot/test/gc/startup_warnings/TestParNewSerialOld.java	Thu Nov 27 21:02:13 2014 +0100
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2013, 2024, 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
@@ -24,7 +24,7 @@
 /*
 * @test TestParNewSerialOld
 * @key gc
-* @bug 8006398
+* @bug 8065972
 * @summary Test that the deprecated ParNew+SerialOld combination print a warning message
 * @library /testlibrary
 */
@@ -38,9 +38,9 @@
   public static void main(String args[]) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseParNewGC", "-version");
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
-    output.shouldContain("warning: Using the ParNew young collector with the Serial old collector is deprecated and will likely be removed in a future release");
-    output.shouldNotContain("error");
-    output.shouldHaveExitValue(0);
+    output.shouldContain("It is not possible to combine the ParNew young collector with the Serial old collector.");
+    output.shouldContain("Error");
+    output.shouldHaveExitValue(1);
   }
 
 }