1421 
1422     /*non-public*/
1423     abstract MethodHandle copyWith(MethodType mt, LambdaForm lf);
1424 
1425     /** Require this method handle to be a BMH, or else replace it with a "wrapper" BMH.
1426      *  Many transforms are implemented only for BMHs.
1427      *  @return a behaviorally equivalent BMH
1428      */
1429     abstract BoundMethodHandle rebind();
1430 
1431     /**
1432      * Replace the old lambda form of this method handle with a new one.
1433      * The new one must be functionally equivalent to the old one.
1434      * Threads may continue running the old form indefinitely,
1435      * but it is likely that the new one will be preferred for new executions.
1436      * Use with discretion.
1437      */
1438     /*non-public*/
1439     void updateForm(LambdaForm newForm) {
1440         if (form == newForm)  return;
1441         assert(this instanceof DirectMethodHandle && this.internalMemberName().isStatic());
1442         // ISSUE: Should we have a memory fence here?

1443         UNSAFE.putObject(this, FORM_OFFSET, newForm);
1444         this.form.prepare();  // as in MethodHandle.<init>
1445     }
1446 
1447     private static final long FORM_OFFSET;
1448     static {
1449         try {
1450             FORM_OFFSET = UNSAFE.objectFieldOffset(MethodHandle.class.getDeclaredField("form"));
1451         } catch (ReflectiveOperationException ex) {
1452             throw newInternalError(ex);
1453         }
1454     }
1455 }

1421 
1422     /*non-public*/
1423     abstract MethodHandle copyWith(MethodType mt, LambdaForm lf);
1424 
1425     /** Require this method handle to be a BMH, or else replace it with a "wrapper" BMH.
1426      *  Many transforms are implemented only for BMHs.
1427      *  @return a behaviorally equivalent BMH
1428      */
1429     abstract BoundMethodHandle rebind();
1430 
1431     /**
1432      * Replace the old lambda form of this method handle with a new one.
1433      * The new one must be functionally equivalent to the old one.
1434      * Threads may continue running the old form indefinitely,
1435      * but it is likely that the new one will be preferred for new executions.
1436      * Use with discretion.
1437      */
1438     /*non-public*/
1439     void updateForm(LambdaForm newForm) {
1440         if (form == newForm)  return;

1441         // ISSUE: Should we have a memory fence here?
1442         newForm.prepare();  // as in MethodHandle.<init>
1443         UNSAFE.putObject(this, FORM_OFFSET, newForm);

1444     }
1445 
1446     private static final long FORM_OFFSET;
1447     static {
1448         try {
1449             FORM_OFFSET = UNSAFE.objectFieldOffset(MethodHandle.class.getDeclaredField("form"));
1450         } catch (ReflectiveOperationException ex) {
1451             throw newInternalError(ex);
1452         }
1453     }
1454 }