[concurrency-interest] Immutable object conundrums

Doug Lea dl at cs.oswego.edu
Tue Jun 30 16:46:38 EDT 2009

Peter Veentjer wrote:

> PS: Do you have a reference to the other concurrency features that are
> going to be added (apart from the fences and the fork/join
> functionality) to Java 7?

Definitely planned classes are in package jsr166y --
ForkJoin, Phasers, TransferQueue, ThreadLocalRandom. See

Plus Fences, which can't be previewed in jsr166y since
it relies on JVM support. See

Plus possibly some sort of customized hash map.
The main reason for delay on that is algorithmic:
Efficient support for features like eviction and
memoization across a large enough range of
policies to be worth supporting in concurrent maps is not a
fully solved problem. I want to make sure that
we offer only that range of them for which we are
very sure we can support well, but without closing
the door to future algorithmic overhauls.


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