--- old/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/z/ZBarrier.java	2018-01-13 12:14:31.376604521 +0900
+++ new/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/z/ZBarrier.java	2018-01-13 12:14:31.109603798 +0900
@@ -26,8 +26,23 @@
 
 import sun.jvm.hotspot.debugger.Address;
 import sun.jvm.hotspot.runtime.VM;
+import sun.jvm.hotspot.types.TypeDataBase;
+import sun.jvm.hotspot.types.WrongTypeException;
 
 class ZBarrier {
+
+    private static int ZGlobalPhase;
+    private static int ZPhaseRelocate;
+
+    static {
+        VM.registerVMInitializedObserver((o, d) -> initialize(VM.getVM().getTypeDataBase()));
+    }
+
+    private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
+        ZGlobalPhase = db.lookupIntConstant("ZGlobalPhase").intValue();
+        ZPhaseRelocate = db.lookupIntConstant("ZPhaseRelocate").intValue();
+    }
+
     private static boolean is_weak_good_or_null_fast_path(Address addr) {
         return ZAddress.is_weak_good_or_null(addr);
     }
@@ -37,7 +52,7 @@
     }
 
     private static boolean during_relocate() {
-        return ZGlobals.ZGlobalPhase() == ZGlobals.ZPhaseRelocate;
+        return ZGlobalPhase == ZPhaseRelocate;
     }
 
     private static Address relocate(Address addr) {