--- old/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	2015-04-01 13:17:07.179820158 +0200
+++ new/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	2015-04-01 13:17:07.055820164 +0200
@@ -1770,6 +1770,11 @@
 
   _g1h = this;
 
+  _workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads,
+                          /* are_GC_task_threads */true,
+                          /* are_ConcurrentGC_threads */false);
+  _workers->initialize_workers();
+
   _allocator = G1Allocator::create_allocator(_g1h);
   _humongous_object_threshold_in_words = HeapRegion::GrainWords / 2;