Thread Pools in Java

Executor Framework

Main Components

  1. ExecutorService > Executor > ExecutorService
  2. ThreadPoolExecutor > Executor > ExecutorService > AbstraceExecutorService > ThreadPoolExecutor > execute() > submit() > invokeAny() > invokeAll() > shutdown() -- soft shutdown > shutdownNow() -- a waiting ExecutorSErvice will cause the JVM to kee running
  3. ScheduledThreadPoolExecutor > Executor > ExecutorService > AbstraceExecutorService > ThreadPoolExecutor > ScheduledThreadPoolExecutor > Executor > ExecutorService > ScheduledExecutorService > ScheduledThreadPoolExecutor

Fork/Join Pool Framework

This framework first ‘fork’ the given task, processing it, and then ‘join’.

Main Components

  1. ForkJoinPool > Executor > ExecutorService > AbstraceExecutorService > ForkJoinPool
  2. ForkJoinWorkerThread > Thread > ForkJoinWorkerThread Each of ForkJoinWorkerThread contains double-ended queue (deque), which stores forked tasks.
    By using this deque and Work Stealing Algorithm, Fork/Join Pool framework allows one thread to work for multiple (especially recursive) tasks.

Spring

  1. ThreadPoolTaskExecutor

    > Executor -- java.util.concurrent
    > TaskExecutor -- org.springframework.core.task
        > AsyncTaskExecutor
            > SchedulingTaskExecutor
                > ThreadPoolTaskExecutor

> ThreadFactory -- java.util.concurrent
> CustomizableThreadCreator -- org.springframework.scheduling ...
    > CustomizableThreadFactory
        > ExecutorConfigurationSupport
            > ThreadPoolTaskExecutor


> Executor -- java.util.concurrent
    > TaskExecutor -- org.springframework.core.task
        > AsyncTaskExecutor
            > AsyncListenableTaskExecutor
                > ThreadPoolTaskExecutor