RFR: Classic problem 02 producer consumer problem

[Michael Mirwaldt]

This sample implements some solutions from the wikipedia article about the producer-consumer-problem on https://en.wikipedia.org/wiki/Producer%E2%80%93consumer_problem .
It contains these solutions:
- _OneProducerOneConsumer_ with semaphores
- _FlawedTwoProducersOneConsumer_ with semaphores in which the producers sometimes use the same index for their items and overwrite each others item
- _FixedTwoProducersOneConsumer_ with semaphores which uses an extra lock for the index so that the producers never use the same index for their items
- _Lock_ doesn't use any sempahores but a reentrant lock with two conditions. It supports many producers and many consumers
- _AtomicIntegers_ neither uses any semaphores but two atomic integers and supports one producer and one consumer.

I have decided not to implement the last solution with finite-range single writer registers in the wikipedia article. It looked far too complicated to me.

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Commit messages:
 - Merge branch 'openjdk:master' into ClassicProblem_02_ProducerConsumerProblem
 - added initial draft of ClassicProblem_02_ProducerConsumerProblem for a PR
 - Setting my user name and email
 - Merge branch 'master' of https://github.com/mmirwaldt/jcstress
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - reviewed ClassicProblem_01_DiningPhilosophers the first time
 - Merge branch 'openjdk:master' into ClassicProblem_01_DiningPhilosophers
 - improved comment and ResourceHierarchy solution in ClassicProblem_01_DiningPhilosophers
 - added OneDinerFewer solution to ClassicProblem_01_DiningPhilosophers
 - ... and 14 more: https://git.openjdk.java.net/jcstress/compare/10bb0008...27ea057f

Changes: https://git.openjdk.java.net/jcstress/pull/102/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jcstress&pr=102&range=00
  Stats: 312 lines in 1 file changed: 312 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/102.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/102/head:pull/102

PR: https://git.openjdk.java.net/jcstress/pull/102