--- old/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	2018-06-11 15:58:46.229648392 +0200
+++ new/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	2018-06-11 15:58:46.018641140 +0200
@@ -3249,6 +3249,9 @@
     if (process_symbols) {
       SymbolTable::clear_parallel_claimed_index();
     }
+    if (process_strings) {
+      StringTable::reset_dead_counter();
+    }
   }
 
   ~G1StringAndSymbolCleaningTask() {
@@ -3262,6 +3265,9 @@
         "symbols: " SIZE_FORMAT " processed, " SIZE_FORMAT " removed",
         strings_processed(), strings_removed(),
         symbols_processed(), symbols_removed());
+    if (_process_strings) {
+      StringTable::finish_dead_counter();
+    }
   }
 
   void work(uint worker_id) {