Package java8.util.concurrent

The Java 7 and Java 8 utility classes commonly used in concurrent programming.

See: Description

Interface Summary

Interface	Description
ForkJoinPool.ForkJoinWorkerThreadFactory	Factory for creating new ForkJoinWorkerThreads.
ForkJoinPool.ManagedBlocker	Interface for extending managed parallelism for tasks running in ForkJoinPools.

Class Summary

Class	Description
ConcurrentMaps	A place for static default implementations of the new Java 8 default interface methods and static interface methods in the ConcurrentMap interface.
CountedCompleter<T>	A ForkJoinTask with a completion action performed when triggered and there are no remaining pending actions.
ForkJoinPool	An ExecutorService for running ForkJoinTasks.
ForkJoinTask<V>	Abstract base class for tasks that run within a ForkJoinPool.
ForkJoinWorkerThread	A thread managed by a ForkJoinPool, which executes ForkJoinTasks.
Phaser	A reusable synchronization barrier, similar in functionality to CyclicBarrier and CountDownLatch but supporting more flexible usage.
RecursiveAction	A recursive resultless ForkJoinTask.
RecursiveTask<V>	A recursive result-bearing ForkJoinTask.
ThreadLocalRandom	A random number generator isolated to the current thread.

Exception Summary

Exception	Description
CompletionException	Exception thrown when an error or other exception is encountered in the course of completing a result or task.

Package java8.util.concurrent Description

The Java 7 and Java 8 utility classes commonly used in concurrent programming.

Memory Consistency Properties

Chapter 17 of The Java™ Language Specification defines the happens-before relation on memory operations such as reads and writes of shared variables. The results of a write by one thread are guaranteed to be visible to a read by another thread only if the write operation happens-before the read operation. The synchronized and volatile constructs, as well as the Thread.start() and Thread.join() methods, can form happens-before relationships. In particular:

• Each action in a thread happens-before every action in that thread that comes later in the program's order.
• An unlock (synchronized block or method exit) of a monitor happens-before every subsequent lock (synchronized block or method entry) of that same monitor. And because the happens-before relation is transitive, all actions of a thread prior to unlocking happen-before all actions subsequent to any thread locking that monitor.
• A write to a volatile field happens-before every subsequent read of that same field. Writes and reads of volatile fields have similar memory consistency effects as entering and exiting monitors, but do not entail mutual exclusion locking.
• A call to start on a thread happens-before any action in the started thread.
• All actions in a thread happen-before any other thread successfully returns from a join on that thread.

Since:

1.8