8315880: change LockingMode default from LM_LEGACY to LM_LIGHTWEIGHT

Reviewed-by: dholmes, rkennke, stefank

Author: Daniel D. Daugherty

src/hotspot/share/runtime/globals.hpp

@@ -1986,11 +1986,11 @@ const int ObjectAlignmentInBytes = 8;
              "Mark all threads after a safepoint, and clear on a modify "   \
              "fence. Add cleanliness checks.")                              \
                                                                             \
-  product(int, LockingMode, LM_LEGACY,                                      \
+  product(int, LockingMode, LM_LIGHTWEIGHT,                                 \
           "Select locking mode: "                                           \
           "0: monitors only (LM_MONITOR), "                                 \
-          "1: monitors & legacy stack-locking (LM_LEGACY, default), "       \
-          "2: monitors & new lightweight locking (LM_LIGHTWEIGHT)")         \
+          "1: monitors & legacy stack-locking (LM_LEGACY), "                \
+          "2: monitors & new lightweight locking (LM_LIGHTWEIGHT, default)") \
           range(0, 2)                                                       \
                                                                             \
   product(uint, TrimNativeHeapInterval, 0, EXPERIMENTAL,                    \