--- old/src/share/vm/gc/g1/g1CollectedHeap.cpp	2017-04-11 15:28:29.612307178 +0200
+++ new/src/share/vm/gc/g1/g1CollectedHeap.cpp	2017-04-11 15:28:29.477303066 +0200
@@ -1612,7 +1612,7 @@
   aligned_expand_bytes = align_size_up(aligned_expand_bytes,
                                        HeapRegion::GrainBytes);
 
-  log_debug(gc, ergo, heap)("Expand the heap. requested expansion amount:" SIZE_FORMAT "B expansion amount:" SIZE_FORMAT "B",
+  log_debug(gc, ergo, heap)("Expand the heap. requested expansion amount: " SIZE_FORMAT "B expansion amount: " SIZE_FORMAT "B",
                             expand_bytes, aligned_expand_bytes);
 
   if (is_maximal_no_gc()) {