This package contains concurrency classes and utilities that are not available in java.util.concurrent.
It contains the Mutex class and Sync interface taken as is, with fixes for checkstyle and
javadoc errors from version 1.3.4 of Doug Lea's concurrency package.
See http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html