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POIs my ThreadPoolExecutor leaking memory?
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copied!<p>I'm using a <a href="http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html" rel="nofollow"><code>ThreadPoolExecutor</code></a> to run tasks. The backend is a <a href="http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/SynchronousQueue.html" rel="nofollow"><code>SynchronousQueue</code></a>, so if the executor is already perfoming a task, it throws the <a href="http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/RejectedExecutionException.html" rel="nofollow"><code>RejectedExecutionException</code></a>. Here's a simple test case:</p> <pre><code>public class ExecutorTest { final static Worker worker = new Worker(); public static void main(String[] args) { ThreadPoolExecutor executor = new ThreadPoolExecutor(1, 1, 0L, TimeUnit.MILLISECONDS, new SynchronousQueue<Runnable>()); while (true) { try { executor.execute(worker); }catch (RejectedExecutionException e) { } } } static class Worker implements Runnable { private int i = 0; private long start = System.currentTimeMillis(); @Override public void run() { try { Thread.sleep(1000); System.out.println(++i + " " + (System.currentTimeMillis() - start)); } catch (InterruptedException ex) { } } } } </code></pre> <p>The expected bahavious is: Execute the worker and after sleeping for a second, print out i (representing how often the worker has been executed so far) and the amount of milliseconds since the worker was created. So I'm expecting:</p> <pre><code>1 1015 2 2015 3 3016 4 4017 </code></pre> <p>This works fine for a while, but after almost on hour:</p> <pre><code>2919 2922196 2920 2942951 2921 2990407 </code></pre> <p>So the amount of time between one worker execution and the next one is 20 seconds (2919->2920) and 38 seconds (2920->2921) and so forth. Everything becomes extremely slow and the jvm spends a lot of time in garbage collection. Finally (after a few days) I run into an OutOfMemoryError.</p> <p>I'm running this with -Xmx8M (I assume the effect appears much later with more heap space) on Oracle's JVM 1.7.0_07 on a 64bit Linux machine. I'd appreciate any pointers, but probably I'm just missing the obvious.</p>

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