diff -r e92153ed8bdc -r 29b0d0b61615 src/hotspot/share/gc/shared/stringdedup/stringDedupTable.cpp
--- a/src/hotspot/share/gc/shared/stringdedup/stringDedupTable.cpp	Mon Nov 25 12:30:24 2019 +0100
+++ b/src/hotspot/share/gc/shared/stringdedup/stringDedupTable.cpp	Mon Nov 25 12:31:39 2019 +0100
@@ -589,7 +589,7 @@
 }
 
 size_t StringDedupTable::claim_table_partition(size_t partition_size) {
-  return Atomic::add(partition_size, &_claimed_index) - partition_size;
+  return Atomic::add(&_claimed_index, partition_size) - partition_size;
 }
 
 void StringDedupTable::verify() {