IZ99243: USE OF JVMTI AGENT PREVENTS OBJECT FINALIZATION AFTER APPLYING APAR IV11135

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: The IBM Java 6 JVM fails to perform finalization
    of objects when the following conditions are met:
    .
    1. The Just-In-Time compiler is enabled.
    .
    2. A JVMTI agent is in use.
    .
    Not finalizing objects can cause allocated resources (such as
    file descriptors) to never be freed, leading to possible "Too
    many open files" exceptions or OutOfMemoryErrors.
    .
    Stack Trace: N/A
    .
    

Local fix

  • This issue can be circumvented with the JVM option
    -Xjit:forceFullSpeedDebug. Note that this may cause severe
    performance degradation. Another workaround is to prevent the
    compilation of Object constructors with this option:
    .
    -Xjit:dontInline={java/lang/Object.<init>*},exclude={java/lang/O
    bject.<init>*}
    

Problem summary

  • When a JVMTI agent is attached to the JVM, the JIT compiler is
    forced to disable certain optimizations to ensure correctness.
    In this restricted mode ("HCR mode"), the JIT compiler was
    unable to recognize that certain classes of objects needed to be
    finalized.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.0 SR9 FP3
    6.0.1 GA FP1
    .
    The JIT compiler has been updated to generate correct code for
    object finalization under HCR mode.
    .
    To obtain the fix:
    Install build 20110405 or later
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ99243

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-04-26

  • Closed date

    2011-05-10

  • Last modified date

    2011-12-20

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R600 PSY

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

6.0

Reference #:

IZ99243

Modified date:

2011-12-20

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