src/java.base/share/classes/java/util/concurrent/locks/LockSupport.java

@@ -139,11 +139,11 @@
 public class LockSupport {
     private LockSupport() {} // Cannot be instantiated.
 
     private static void setBlocker(Thread t, Object arg) {
         // Even though volatile, hotspot doesn't need a write barrier here.
-        U.putObject(t, PARKBLOCKER, arg);
+        U.putReference(t, PARKBLOCKER, arg);
     }
 
     /**
      * Makes available the permit for the given thread, if it
      * was not already available.  If the thread was blocked on

@@ -289,11 +289,11 @@
      * @since 1.6
      */
     public static Object getBlocker(Thread t) {
         if (t == null)
             throw new NullPointerException();
-        return U.getObjectVolatile(t, PARKBLOCKER);
+        return U.getReferenceVolatile(t, PARKBLOCKER);
     }
 
     /**
      * Disables the current thread for thread scheduling purposes unless the
      * permit is available.