--- old/src/hotspot/share/runtime/globals.hpp	2018-01-24 11:00:50.360735550 +0100
+++ new/src/hotspot/share/runtime/globals.hpp	2018-01-24 11:00:49.857713712 +0100
@@ -1438,10 +1438,11 @@
           "Verify forwarding tables (for debugging only)")                  \
                                                                             \
   product(bool, ZWeakRoots, true,                                           \
-          "Treat JNI WeakGlobalRefs and StringTable as weak roots")         \
+          "Treat JNI WeakGlobalRefs and StringTable as weak roots "         \
+          "(for debugging only)")                                           \
                                                                             \
   product(bool, ZConcurrentJNIWeakGlobalHandles, true,                      \
-          "Clean JNI WeakGlobalRefs concurrently")                          \
+          "Clean JNI WeakGlobalRefs concurrently (for debugging only)")     \
                                                                             \
   product(size_t, ZMarkStacksMax, NOT_LP64(512*M) LP64_ONLY(8*G),           \
           "Maximum number of bytes allocated for marking stacks")           \