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IV70546: ADDRESS LOCKING CONTENTION IN JAVA/LANG/CLASS.GETGENERICINTERFAC ES() AND JAVA/LANG/CLASS.GETCLASSREPOSITORY().

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APAR status

  • Closed as program error.

Error description

  • Error Message: Performance issues may be noticed in code that
    heavily utilizes the java.lang.Class.getGenericInterface() or
    java/lang/Class.getClassRepository() methods.
    .
    Stack Trace: A javacore taken during the time of the issue will
    show multiple threads blocked on the following
    stack:4XESTACKTRACE                at
    java/util/Hashtable.get(Hashtable.java:  617(Compiled
    Code))5XESTACKTRACE                   (entered lock:
    java/util/Hashtable@0x0000000044923FE0, entry count:
    1)4XESTACKTRACE                at
    java/lang/Class.getClassRepository   Class.java:2045(Compiled
    Code))4XESTACKTRACE                at
    java/lang/Class.getGenericInterfaces (Class.java:2081(Compiled
    Code))
    .
    

Local fix

Problem summary

  • The performance issue is due to a synchronization bottleneck in
    the implementation of java/lang/Class and java/lang/Classloader.
    

Problem conclusion

  • The jvm has been updated to remove the synchronization
    bottleneck that caused the issue.
    .
    This APAR will be fixed in the following Java Releases:
       6 R1 SR8 FP4   (6.1.8.4)
       7    SR9       (7.0.9.0)
       8    SR1       (8.0.1.0)
       7 R1 SR3       (7.1.3.0)
    .
    Contact your IBM Product's Service Team for these Service
    Refreshes and Fix Packs.
    For those running stand-alone, information about the Service
    Refreshes and Fix Packs can be found at:
               https://www.ibm.com/developerworks/java/jdk/
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV70546

  • Reported component name

    J9 COMMON CODE

  • Reported component ID

    620700127

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2015-03-04

  • Closed date

    2015-03-04

  • Last modified date

    2015-03-04

  • 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

    J9 COMMON CODE

  • Fixed component ID

    620700127

Applicable component levels

  • R260 PSY

       UP

  • R270 PSY

       UP



Document information

More support for: Runtimes for Java Technology
Virtual Machine

Software version: 260

Reference #: IV70546

Modified date: 04 March 2015