RFR: JDK-8232806: The LambdaMetaFactory eagerly initializes generated lambdas

[Vojin Jovanovic]

Hi all, 

This email proposes a change to the LambdaMetaFactory that allows to disable eager initialization (with Unsafe) of generated lambdas. This is needed by the GraalVM Native Image, as initialization of lambdas during AOT compilation breaks our heap snapshotting (via initialization of interfaces with default methods that are super-types of a lambda). We have started from the original proposal that stores lambda instances in the static fields

  https://github.com/graalvm/labs-openjdk-11/commit/00b9ecd85dedd0411837eee33635dd83e8b7def8

and initializes them with Unsafe as an optimization 

   https://github.com/graalvm/labs-openjdk-11/commit/273e8590a7b57c0c10d9213ca9e0ba581e2817b8

After the discussion with Brian Goetz, we have trimmed down to the following change:

  https://bugs.openjdk.java.net/secure/attachment/85247/lambda-disable-initialization.diff

The evolution of this change can be found at the issue: 

 https://bugs.openjdk.java.net/browse/JDK-8232806
 
Cheers,
- Vojin