IV22237: REFLECTIVE FIELD MODIFICATION LEADS TO INCORRECT METHOD CALLS

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APAR status

  • Closed as program error.

Error description

  • Error Message: When a base class B is extended by a subclass C
    and one of its public methods M is overridden, a call to C.M can
    incorrectly execute B.M, when the following conditions are met:
    - a third class defines F as a private static field of type B;
    - the field is modified by external code, via reflection, to
    point to an object of type C;
    - F.M is called in a hot loop.
    .
    Stack Trace: N/A
    .
    

Local fix

  • This problem can be avoided by setting the JVM command-line
    option -Xjit:disablelookahead.
    

Problem summary

  • The JIT compiler attempted to optimize the hot call by
    devirtualizing the call to M, but its analysis resulted in an
    incorrect type for the private static field F when it could be
    modified via reflection.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.1 SR3
    7.0.0 SR2
    6.0.0 SR11
    5.0.0 SR13FP2
    .
    The JIT compiler has been updated to perform the type analysis
    correctly.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV22237

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-06-06

  • Closed date

    2012-06-06

  • Last modified date

    2012-06-06

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

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

    IV22238 PM66904

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R260 PSY

       UP

  • R600 PSY

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

260

Reference #:

IV22237

Modified date:

2012-06-06

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