IV34570: THE ADJUSTMENT OF COMPUTER CLOCK WHILE JAVA PROGRAM IS RUNNING C AN CREATE AN EFFECT OF 'TIME GOES BACKWARDS'

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: JVMDUMP039I Processing dump event "systhrow",
    detail "java/lang/OutOfMemoryError" at 2012/04/01 23:28:40 -
    please wait.
    JVMDUMP032I JVM requested System dump using
    '/tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/core.2
    0120401.232840.21717.0001.dmp' in response to an event
    JVMDUMP010I System dump written to
    /tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/core.20
    120401.232840.21717.0001.dmp
    JVMDUMP032I JVM requested Heap dump using
    '/tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/heapdu
    mp.20120401.232840.21717.0002.phd' in response to an event
    JVMDUMP010I Heap dump written to
    /tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/heapdum
    p.20120401.232840.21717.0002.phd
    JVMDUMP032I JVM requested Java dump using
    '/tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/javaco
    re.20120401.232840.21717.0003.txt' in response to an event
    JVMDUMP010I Java dump written to
    /tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/javacor
    e.20120401.232840.21717.0003.txt
    JVMDUMP032I JVM requested Snap dump using
    '/tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/Snap.2
    0120401.232840.21717.0004.trc' in response to an event
    JVMDUMP010I Snap dump written to
    /tmp/bld_106960/cmdLineTester_classesdbgddrext/106026550/Snap.20
    120401.232840.21717.0004.trc
    JVMDUMP013I Processed dump event "systhrow", detail
    "java/lang/OutOfMemoryError".
    Exception in thread "Thread-20" java.lang.OutOfMemoryError: Java
    heap space
     at
    java.lang.StringBuffer.ensureCapacityImpl(StringBuffer.java:338)
     at java.lang.StringBuffer.append(StringBuffer.java:204)
     at Test$StreamMatcher.run(Unknown Source)
    .
    Stack Trace: N/A
    .
    "!!! The external wall clock shift (backwards) detected !!!"
    message in GC verbose log
    

Local fix

  • This is extremely intermittent issue occur if computer clock was
    adjusted while Java program was running. This is
    -Xgcpolicy:gencon specific issue, so this issue can be worked
    around using another GC policy or just re-running Java program.
    

Problem summary

  • An adjustment of computer clock while Java program is running
    can create an effect of "time goes backwards" when GC End time
    is earlier then GC Start time. This might be a reason for
    mistake in calculation of duration of GC Cycle (very large
    number). The result of this might be unnecessary throwing OOM or
    even crash in Java VM
    

Problem conclusion

  • This defect will be fixed in:
    7.0.0 SR3
    6.0.1 SR4
    .
    Added detection of "time goes backwards" situation and adjust
    required calculations.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV34570

  • 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

    2013-01-11

  • Closed date

    2013-01-11

  • Last modified date

    2013-01-11

  • 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



Rate this page:

(0 users)Average rating

Add comments

Document information


More support for:

Runtimes for Java Technology
Virtual Machine

Software version:

260

Reference #:

IV34570

Modified date:

2013-01-11

Translate my page

Machine Translation

Content navigation