IBM Support

IV46485: OPTIMIZE RUN-TIME ARRAY TYPE CHECK

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APAR status

  • Closed as program error.

Error description

  • Error Message: The performance of Java applications that use
    arrays of interfaces may suffer from slow run-time type checks.
    .
    Stack Trace: N/A
    .
    

Local fix

  • N/A
    

Problem summary

  • The Java Language Specification requires a run-time type check
    when an object is stored into an array. If the type of the
    object is not compatible with that of the array, an
    ArrayStoreException must be thrown. This type check can be
    time-consuming if the array component type is an interface.
    

Problem conclusion

  • This defect will be fixed in:
    7.0.0 SR6
    6.0.1 SR7
    .
    An experimental feature to optimize the run-time type checks
    during array writes (where applicable) has been added to the JIT
    compiler. This feature is DISABLED by default in Java 6.0.1 and
    Java 7. The experimental feature can be enabled with the
    -Xjit:enableArrayStoreCheckInstanceOpt option. This option is
    UNSUPPORTED unless used at the direction of IBM JIT compiler
    support. The feature is expected to be supported officially in
    the next major release of IBM Java.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV46485

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-07-31

  • Closed date

    2013-08-02

  • Last modified date

    2013-08-09

  • 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

  • R260 PSY

       UP



Document information

More support for: Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version: 260

Reference #: IV46485

Modified date: 09 August 2013