RFR(m): JEP 269 initial API and skeleton implementation (JDK-8139232)

[John Rose]

On Nov 23, 2015, at 10:26 PM, Stuart Marks <stuart.marks at oracle.com> wrote:
> 
> Please review these API and implementation changes that comprise the first integration of JEP 269. I intend to push this under the "initial API and skeleton implementation" subtask, JDK-8139232.

Please strengthen the specification to assert that the new immutables are in fact value-based.

http://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html <http://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html>

This will prevent people from relying on their identity (acmp) and synchronization (monitorenter).
It will allow optimizations more freedom to use flatter storage formats and to reuse list values.

If we don't do this now, then we will not be able to retroactively make or enforce the claim,
and the optimizations will be impossible.

— John