IJ49911: STRING COMPARISON FAILURES CAUSED BY STRING COMPRESSION

APAR status

• Closed as program error.

Error description

• Error Message: Various error messages may be produced, depending
  on which particular operation failed
  .
  Stack Trace: An example stack trace is a NoSuchMethodException
  thrown after a call to java.lang.Class.getDeclaredMethod(),
  caused by an underlying String comparison failure which in this
  case prevents a method from being found by its name:
  Exception in thread "main" java.lang.NoSuchMethodException:
  Test.getä()
      at
  java.base/java.lang.Class.newNoSuchMethodException(Class.java:64
  9)
      at
  java.base/java.lang.Class.throwExceptionOrReturnNull(Class.java:
  1447)
      at
  java.base/java.lang.Class.getMethodHelper(Class.java:1533)
      at
  java.base/java.lang.Class.getDeclaredMethod(Class.java:1121)
      ...
  .
  

Local fix

• Disable String comparison with this command line option:
      -XX:-CompactStrings
  

Problem summary

• The problem is caused by a mishandling of compressed String
  Unicode data in the OpenJ9 JVM. String compression was first
  enabled by default for JDK 11 and later in OpenJ9 0.41.0, so
  issues may manifest for the first time when running on Semeru
  11.0.21.0, 17.0.9.0, and 21.0.1.0.
  The problem may also manifest with IBM Java 8 and Semeru 8 if
  String compression has been explicitly enabled using the
  -XX:+CompactStrings command line option.
  

Problem conclusion

• The issue has been addressed in OpenJ9 0.43.0. See OpenJ9 issue
  18791 for more information:
  https://github.com/eclipse-openj9/openj9/issues/18791
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
     11              11.0.22.0
     17              17.0.10.0
  IBM SDK, Java Technology Edition
     8    SR8 FP21   8.0.8.21
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For non z/OS operating systems:
    - IBM Semeru Runtimes, Version 11 and later
      https://www.ibm.com/semeru-runtimes/downloads/
    - IBM SDK, Java Technology Edition, Version 8
      https://www.ibm.com/support/pages/java-sdk-downloads/
  - For the z/OS operating system:
    - Java SDK Products on z/OS
      https://www.ibm.com/support/pages/java-sdk-products-zos
  

Temporary fix

Comments

APAR Information

• 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