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  1. JDK
  2. JDK-8277072

ObjectStreamClass caches keep ClassLoaders alive

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    • b02
    • generic
    • generic
    • Verified

    Backports

      Description

        The caches in ObjectStreamClass basically map WeakReference<Class> to SoftReference<ObjectStreamClass>, where the ObjectStreamClass also references the same Class. That means that the cache entry, and thus the class and its class-loader, will not get reclaimed, unless the GC determines that memory pressure is very high.

        However, this seems bogus, because that unnecessarily keeps ClassLoaders and all its classes alive much longer than necessary: as soon as a ClassLoader (and all its classes) become unreachable, there is no point in retaining the stuff in OSC's caches.

        This can be demonstrated by compiling the attached .java files, and run:
        java TestObjectStreamClass

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            backported by

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8283588 ObjectStreamClass caches keep ClassLoaders alive

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8283678 ObjectStreamClass caches keep ClassLoaders alive

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8284129 ObjectStreamClass caches keep ClassLoaders alive

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8293079 ObjectStreamClass caches keep ClassLoaders alive

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8293080 ObjectStreamClass caches keep ClassLoaders alive

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            duplicates

            Enhancement - null JDK-8199589 ObjectStreamClass does not provide a mechanism to clear the cache

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Closed
            relates to

            Bug - A problem which impairs or prevents the functions of the product. JDK-8283276 java/io/ObjectStreamClass/ObjectStreamClassCaching.java fails with various GCs

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8280041 Retry loop issues in java.io.ClassCache

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Closed

            Enhancement - null JDK-8278065 Refactor subclassAudits to use ClassValue

            • P3 - Major loss of function.
            • Resolved

            Enhancement - null JDK-8199589 ObjectStreamClass does not provide a mechanism to clear the cache

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Closed
            links to

            Commit Commit openjdk/jdk11u-dev/118ec617

            Commit Commit openjdk/jdk17u-dev/7d132f5e

            Commit Commit openjdk/jdk18u/76e25e64

            Commit Commit openjdk/jdk/8eb453ba

            Review Review openjdk/jdk11u-dev/869

            Review Review openjdk/jdk17u-dev/210

            Review Review openjdk/jdk18/117

            Review Review openjdk/jdk18u/36

            Review Review openjdk/jdk/6375

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                rkennke Roman Kennke
                rkennke Roman Kennke
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