RFR: 8249080 - Reduce MemberName class dependency on MethodHandles

[Bob Vandette]

> On Jul 8, 2020, at 12:08 PM, Mandy Chung <mandy.chung at oracle.com> wrote:
> 
> 
> 
> On 7/8/20 8:19 AM, Bob Vandette wrote:
>> Please review this RFE for JDK 16 that reduces a class dependency in the MethodHandles.Lookup class.
>> 
>> The ensureInitialized method from MethodHandles.Lookup creates a transient MemberName object only
>> to be used to throw an exception. This exception can be created in a more efficient manner without
>> using this class reducing the number of classes required. This reduction in dependencies is beneficial
>> to the GraalVM native-image tool and will be useful for future Leyden native image implementations. 
>> 
> 
> I agree that Lookup::ensureInitialized should not depend MemberName.  This refactoring seems a reasonable approach.
> 
>> RFE:
>> 
>> 
>> https://bugs.openjdk.java.net/browse/JDK-8249080
>> 
>> 
>> WEBREV:
>> 
>> 
>> http://cr.openjdk.java.net/~bobv/8249080/webrev.01/
>> 
>> 
>> 
> 3537         /**
> 3538          * Perform necessary <a href="MethodHandles.Lookup.html#secmgr">access checks</a>
> 3539          * for findClass or accessClass.
> 3540          */
> 
> This should also mention `ensureInitialized`.  

Ok.

> 
> 3578             if (m == null) {
> 3579             // Step 2b:
> 3580                 if (!fullPowerLookup) {
> 3581                     smgr.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
> 3582                 }
> 3583                 return;
> 3584             }
> 
> This is no longer needed.  Instead, this method should require a non-null MemberName argument.

I was going to remove the null check but was concerned that there might be other cases where the argument 
might be null.

Should I add an assert or just let the NPE happen?

Bob.


> 
> Mandy