diff -r a7c0f60a1294 -r 294e48b4f704 hotspot/src/share/vm/gc/g1/g1RegionToSpaceMapper.cpp
--- a/hotspot/src/share/vm/gc/g1/g1RegionToSpaceMapper.cpp	Mon Sep 28 15:05:02 2015 +0200
+++ b/hotspot/src/share/vm/gc/g1/g1RegionToSpaceMapper.cpp	Tue Sep 29 11:02:08 2015 +0200
@@ -113,7 +113,7 @@
 
   virtual void commit_regions(uint start_idx, size_t num_regions) {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
-      assert(!_commit_map.at(i), err_msg("Trying to commit storage at region %u that is already committed", i));
+      assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i);
       size_t idx = region_idx_to_page_idx(i);
       uint old_refcount = _refcounts.get_by_index(idx);
       bool zero_filled = false;
@@ -128,7 +128,7 @@
 
   virtual void uncommit_regions(uint start_idx, size_t num_regions) {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
-      assert(_commit_map.at(i), err_msg("Trying to uncommit storage at region %u that is not committed", i));
+      assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i);
       size_t idx = region_idx_to_page_idx(i);
       uint old_refcount = _refcounts.get_by_index(idx);
       assert(old_refcount > 0, "must be");