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javamultithreadingconcurrencyexecutorthread-priority

Java Executors: how can I set task priority?

Is there a possibility to set priority to tasks which are executed by Executors? I've found some statements in JCIP about it's possible but I cannot find any example and I cannot find anything related in docs.

From JCIP:

An execution policy specifies the "what, where, when, and how" of task execution, including:

  • ...
  • In what order should tasks be executed (FIFO, LIFO, priority order)?
  • ...

UPD: I realized that I asked not exactly what I wanted to ask. What I really wanted is:

How to use/emulate setting threads priority (i.e. what was thread.setPriority()) with executors framework?

Solution

  • Currently the only concrete implementations of the Executor interface are the ThreadPoolExecutor and the ScheduledThreadpoolExecutor

    Instead of using the utility / factory class Executors, you should create an instance using a constructor.

    You can pass a BlockingQueue to the constructors of the ThreadPoolExecutor.

    One of the implementations of the BlockingQueue, the PriorityBlockingQueue lets you pass a Comparator to a constructor, that way enabling you to decide the order of execution.