https://kevinwang930.github.io/tags/thread-pool/Recent content in Thread-Pool on Kevin wang's blogHugoen-USSun, 05 Jul 2026 00:00:00 +0800https://kevinwang930.github.io/post/java/concurrency/thread-pool-blocking-queue/Sun, 05 Jul 2026 00:00:00 +0800https://kevinwang930.github.io/post/java/concurrency/thread-pool-blocking-queue/<p>A Java thread pool separates <strong>task submission</strong> from <strong>task execution</strong>. Submitting threads hand <code>Runnable</code> objects to an <code>ExecutorService</code>; a set of worker threads removes those tasks and runs them. In <code>ThreadPoolExecutor</code> and <code>ScheduledThreadPoolExecutor</code> the hand-off point between the two sides is a <code>java.util.concurrent.BlockingQueue&lt;Runnable&gt;</code>. The queue therefore decides how tasks are buffered, ordered and throttled, and the pool decides how many threads consume them.</p> <p>This article first enumerates the thread pool and blocking queue types of the JDK. Part 1 then examines the OpenJDK <code>BlockingQueue</code> implementations: the dual-condition bounded buffer, the two-lock design of <code>LinkedBlockingQueue</code>, the heap-backed <code>PriorityBlockingQueue</code>, the zero-capacity rendezvous of <code>SynchronousQueue</code>, and the timed waiting protocol of <code>DelayQueue</code>. Part 2 examines the thread pools built on them: the control state, admission, worker loop, rejection and shutdown of <code>ThreadPoolExecutor</code>, the <code>Executors</code> factories, and the scheduling of <code>ScheduledThreadPoolExecutor</code>.</p>