Java in a Nutshell, 5th Edition

Name

Executors

Synopsis

This utility class defines static factory methods for creating ExecutorService and ScheduledExecutorService objects. Each of the factory methods has a variant that allows you to explicitly specify a ThreadFactory. newSingleThreadExecutor( ) returns an ExecutorService that uses a single thread and an unbounded queue of waiting tasks. newFixedThreadPool( ) returns an ExecutorService that uses a thread pool with the specified number of threads and an unbounded queue. newCachedThreadPool( ) returns an ExecutorService that does not queue tasks but instead creates as many threads as are needed. When a task terminates, its thread is cached for reuse. Cached threads are allowed to terminate if they remain unused for 60 seconds.

newSingleThreadScheduledExecutor( ) returns a ScheduledExecutorService that uses a single thread for running tasks. newScheduledThreadPool( ) returns a ScheduledExecutorService that uses a thread pool of the specified size.

The factory methods of this class typically return instances of ThreadPoolExecutor and ScheduledThreadPoolExecutor. If the returned objects are cast to these implementing types, they can be configured (to change the thread pool size, for example). If you want to prevent this from happening, use the unconfigurableExecutorService( ) and unconfigurableScheduledExecutorService( ) methods to obtain wrapper objects that implement only the ExecutorService and ScheduledExecutorService methods and do not permit configuration.

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