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  1. JDK
  2. JDK-8172726

ForkJoin common pool retains a reference to the thread context class loader

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        FULL PRODUCT VERSION :
        java version "1.8.0_112"
        Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
        Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)

        ADDITIONAL OS VERSION INFORMATION :
        Microsoft Windows [Version 6.1.7601] (fully patched)

        A DESCRIPTION OF THE PROBLEM :
        There are multiple issues with ForkJoinPool.commonPool

        1. The default thread pool does not change Thread.contextClassLoader to the system class loader. When ForkJoinPool.commonPool is used in a multi-class loader environment (e.g. a JavaEE container) this causes references to be retained to the class loader associated with the code that first uses the pool. This is highly likely to cause a memory leak.

        2. The InnocuousForkJoinWorkerThread does not modify Thread.contextClassLoader so undesirable class loader references are retained even when using the InnocuousForkJoinWorkerThreadFactory

        STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
        Execute this test case:

        https://github.com/markt-asf/memory-leaks/blob/master/src/org/apache/markt/leaks/concurrent/ForkJoinThreadLeak.java

        EXPECTED VERSUS ACTUAL BEHAVIOR :
        EXPECTED -
        The console should report no leaks detected.
        ACTUAL -
        The console reports that a memory leak is detected and use of a profiler confirms the leak.

        REPRODUCIBILITY :
        This bug can be reproduced always.

        ---------- BEGIN SOURCE ----------
        https://github.com/markt-asf/memory-leaks/blob/master/src/org/apache/markt/leaks/concurrent/ForkJoinThreadLeak.java
        ---------- END SOURCE ----------

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                • Assignee:
                  martin Martin Buchholz
                  Reporter:
                  webbuggrp Webbug Group
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                  • Created:
                    Updated:
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