IV43478: A JAVA.LANG.CLASSCASTEXCEPTION HAPPENS WITH A PROXY CLASS GENERA TED BY METHOD NEWPROXYINSTANCE() OF CLASS JAVA.LANG.REFLECT.PROX

APAR status

• Closed as program error.

Error description

• Error Message: An error message similar to the following is
  received:
  
     Caused by: java.lang.ClassCastException: $Proxy6 incompatible
  with <SOME_INTERFACE>
  .
  Stack Trace: N/A
  .
  

Local fix

• This issue can be worked around by disabling the share classes
  cache with the following option:
          -Xshareclasses:none
  

Problem summary

• When a proxy object is generated through the following method in
  java.lang.reflect.Proxy,
     newProxyInstance(ClassLoader loader, Class<?><OSB><CSB>
  interfaces, InvocationHandler h)
    the proxy class (for example $Proxy6) will be generated and
  improperly cached into the share classes cache.  After
    the JVM is restarted, the proxy class ($Proxy6) will be loaded
  from the share classes cache to JVM runtime. It would cause a
    java.lang.ClassCastException if the same proxy class ($Proxy6)
  is cast to some other interface.
  

Problem conclusion

• The JVM has been updated to prevent the improper caching
  information into the share classes cache.
  
  This defect will be fixed in:
  5.0.0 SR12 FP4
  5.0.0 SR13
  6.0.0 SR10
  

Temporary fix

Comments

APAR Information

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

  IZ94639

• 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

• R600 PSY