--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Thu Sep 18 11:04:00 2014 +0200
@@ -4167,7 +4167,7 @@
 // been published), so we do not need to check for
 // uninitialized objects before pushing here.
 void Par_ConcMarkingClosure::do_oop(oop obj) {
-  assert(obj->is_oop_or_null(true), "expected an oop or NULL");
+  assert(obj->is_oop_or_null(true), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   // Check if oop points into the CMS generation
   // and is not marked
@@ -7226,7 +7226,7 @@
 // isMarked() query is "safe".
 bool ScanMarkedObjectsAgainClosure::do_object_bm(oop p, MemRegion mr) {
   // Ignore mark word because we are running concurrent with mutators
-  assert(p->is_oop_or_null(true), "expected an oop or null");
+  assert(p->is_oop_or_null(true), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(p)));
   HeapWord* addr = (HeapWord*)p;
   assert(_span.contains(addr), "we are scanning the CMS generation");
   bool is_obj_array = false;
@@ -7666,7 +7666,7 @@
 }
 
 void PushAndMarkVerifyClosure::do_oop(oop obj) {
-  assert(obj->is_oop_or_null(), "expected an oop or NULL");
+  assert(obj->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   if (_span.contains(addr) && !_verification_bm->isMarked(addr)) {
     // Oop lies in _span and isn't yet grey or black
@@ -7764,7 +7764,7 @@
 
 void PushOrMarkClosure::do_oop(oop obj) {
   // Ignore mark word because we are running concurrent with mutators.
-  assert(obj->is_oop_or_null(true), "expected an oop or NULL");
+  assert(obj->is_oop_or_null(true), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   if (_span.contains(addr) && !_bitMap->isMarked(addr)) {
     // Oop lies in _span and isn't yet grey or black
@@ -7802,7 +7802,7 @@
 
 void Par_PushOrMarkClosure::do_oop(oop obj) {
   // Ignore mark word because we are running concurrent with mutators.
-  assert(obj->is_oop_or_null(true), "expected an oop or NULL");
+  assert(obj->is_oop_or_null(true), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   if (_whole_span.contains(addr) && !_bit_map->isMarked(addr)) {
     // Oop lies in _span and isn't yet grey or black
@@ -7879,7 +7879,7 @@
   // path and may be at the end of the global overflow list (so
   // the mark word may be NULL).
   assert(obj->is_oop_or_null(true /* ignore mark word */),
-         "expected an oop or NULL");
+         err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   // Check if oop points into the CMS generation
   // and is not marked
@@ -7959,7 +7959,7 @@
   // the debugger, is_oop_or_null(false) may subsequently start
   // to hold.
   assert(obj->is_oop_or_null(true),
-         "expected an oop or NULL");
+         err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   HeapWord* addr = (HeapWord*)obj;
   // Check if oop points into the CMS generation
   // and is not marked

--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/promotionInfo.hpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/promotionInfo.hpp	Thu Sep 18 11:04:00 2014 +0200
@@ -73,7 +73,7 @@
     } else {
       res = (PromotedObject*)(_next & next_mask);
     }
-    assert(oop(res)->is_oop_or_null(true /* ignore mark word */), "Not an oop?");
+    assert(oop(res)->is_oop_or_null(true /* ignore mark word */), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(oop(res))));
     return res;
   }
   inline void setNext(PromotedObject* x) {

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp	Thu Sep 18 11:04:00 2014 +0200
@@ -277,7 +277,7 @@
   ++_refs_reached;
 
   HeapWord* objAddr = (HeapWord*) obj;
-  assert(obj->is_oop_or_null(true /* ignore mark word */), "Error");
+  assert(obj->is_oop_or_null(true /* ignore mark word */), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));
   if (_g1h->is_in_g1_reserved(objAddr)) {
     assert(obj != NULL, "null check is implicit");
     if (!_nextMarkBitMap->isMarked(objAddr)) {

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp	Thu Sep 18 11:04:00 2014 +0200
@@ -288,7 +288,7 @@
           while (p < to) {
             Prefetch::write(p, interval);
             oop m = oop(p);
-            assert(m->is_oop_or_null(), "check for header");
+            assert(m->is_oop_or_null(), err_msg("Expected an oop or NULL for header field at " PTR_FORMAT, p2i(m)));
             m->push_contents(pm);
             p += m->size();
           }
@@ -296,7 +296,7 @@
         } else {
           while (p < to) {
             oop m = oop(p);
-            assert(m->is_oop_or_null(), "check for header");
+            assert(m->is_oop_or_null(), err_msg("Expected an oop or NULL for header field at " PTR_FORMAT, p2i(m)));
             m->push_contents(pm);
             p += m->size();
           }

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp	Thu Sep 18 11:04:00 2014 +0200
@@ -2882,7 +2882,7 @@
         start_array->allocate_block(addr);
       }
       oop(addr)->update_contents(cm);
-      assert(oop(addr)->is_oop_or_null(), "should be an oop now");
+      assert(oop(addr)->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(oop(addr))));
     }
   }
 }
@@ -3366,7 +3366,7 @@
 
   oop moved_oop = (oop) destination();
   moved_oop->update_contents(compaction_manager());
-  assert(moved_oop->is_oop_or_null(), "Object should be whole at this point");
+  assert(moved_oop->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(moved_oop)));
 
   update_state(words);
   assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity");

--- a/hotspot/src/share/vm/interpreter/bytecodeInterpreter.inline.hpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/interpreter/bytecodeInterpreter.inline.hpp	Thu Sep 18 11:04:00 2014 +0200
@@ -35,7 +35,7 @@
 #ifdef ASSERT
 #define VERIFY_OOP(o_) \
       if (VerifyOops) { \
-        assert((oop(o_))->is_oop_or_null(), "Not an oop!"); \
+        assert((oop(o_))->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(oop(o_)))); \
         StubRoutines::_verify_oop_count++;  \
       }
 #else

--- a/hotspot/src/share/vm/memory/referenceProcessor.cpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/memory/referenceProcessor.cpp	Thu Sep 18 11:04:00 2014 +0200
@@ -473,7 +473,7 @@
   _discovered_addr = java_lang_ref_Reference::discovered_addr(_ref);
   oop discovered = java_lang_ref_Reference::discovered(_ref);
   assert(_discovered_addr && discovered->is_oop_or_null(),
-         "discovered field is bad");
+         err_msg("Expected an oop or NULL for discovered field at " PTR_FORMAT, p2i(discovered)));
   _next = discovered;
   _referent_addr = java_lang_ref_Reference::referent_addr(_ref);
   _referent = java_lang_ref_Reference::referent(_ref);
@@ -482,7 +482,9 @@
   assert(allow_null_referent ?
              _referent->is_oop_or_null()
            : _referent->is_oop(),
-         "bad referent");
+         err_msg("Expected an oop%s for referent field at " PTR_FORMAT,
+                 (allow_null_referent ? " or NULL" : ""),
+                 p2i(_referent)));
 }
 
 void DiscoveredListIterator::remove() {
@@ -630,7 +632,7 @@
     oop next = java_lang_ref_Reference::next(iter.obj());
     if ((iter.referent() == NULL || iter.is_referent_alive() ||
          next != NULL)) {
-      assert(next->is_oop_or_null(), "bad next field");
+      assert(next->is_oop_or_null(), err_msg("Expected an oop or NULL for next field at " PTR_FORMAT, p2i(next)));
       // Remove Reference object from list
       iter.remove();
       // Trace the cohorts
@@ -979,7 +981,7 @@
   while (iter.has_next()) {
     iter.load_ptrs(DEBUG_ONLY(true /* allow_null_referent */));
     oop next = java_lang_ref_Reference::next(iter.obj());
-    assert(next->is_oop_or_null(), "bad next field");
+    assert(next->is_oop_or_null(), err_msg("Expected an oop or NULL for next field at " PTR_FORMAT, p2i(next)));
     // If referent has been cleared or Reference is not active,
     // drop it.
     if (iter.referent() == NULL || next != NULL) {
@@ -1172,7 +1174,7 @@
 
   HeapWord* const discovered_addr = java_lang_ref_Reference::discovered_addr(obj);
   const oop  discovered = java_lang_ref_Reference::discovered(obj);
-  assert(discovered->is_oop_or_null(), "bad discovered field");
+  assert(discovered->is_oop_or_null(), err_msg("Expected an oop or NULL for discovered field at " PTR_FORMAT, p2i(discovered)));
   if (discovered != NULL) {
     // The reference has already been discovered...
     if (TraceReferenceGC) {

--- a/hotspot/src/share/vm/services/heapDumper.cpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/services/heapDumper.cpp	Thu Sep 18 11:04:00 2014 +0200
@@ -722,7 +722,7 @@
 
       // reflection and sun.misc.Unsafe classes may have a reference to a
       // Klass* so filter it out.
-      assert(o->is_oop_or_null(), "should always be an oop");
+      assert(o->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(o)));
       writer->write_objectID(o);
       break;
     }

--- a/hotspot/src/share/vm/utilities/taskqueue.hpp	Thu Sep 18 11:27:59 2014 +0200
+++ b/hotspot/src/share/vm/utilities/taskqueue.hpp	Thu Sep 18 11:04:00 2014 +0200
@@ -331,7 +331,7 @@
     //            index, &_elems[index], _elems[index]);
     E* t = (E*)&_elems[index];      // cast away volatility
     oop* p = (oop*)t;
-    assert((*t)->is_oop_or_null(), "Not an oop or null");
+    assert((*t)->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(*t)));
     f->do_oop(p);
   }
   // tty->print_cr("END OopTaskQueue::oops_do");