Class file format version bump <was> Re: is ClassLoader.loadClass() supposed to work on module-info classes?

Paul Sandoz paul.sandoz at
Mon Dec 7 08:51:16 UTC 2015

> On 5 Dec 2015, at 00:09, Alex Buckley <alex.buckley at Oracle.COM> wrote:
> On 12/4/2015 11:58 AM, Peter Levart wrote:
>> I know about those options. What I was wanting to know is whether the
>> class file format will change and for what features.
> It's possible that VarHandles will justify a bump to 53.0 because of new semantics for invokevirtual (see JEP 193). Paging Paul Sandoz, how is that JVM Spec update coming along? :-)

(I nearly missed this paging :-) )

Here is the current specdiff (this is updated regularly): <>

At the end of the class summary of VarHandle there are notes on possible updates to the specifications: <>

I will contact you off list about how best to proceed.


> (Yes, changing instruction semantics causes a bump. Changing ldc in SE 5.0 to support class constants bumped 48.0 to 49.0, thus losing the ability to compile code with generics on JDK 5 and run the class files on 1.4.)
> Alex

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