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PM79151: When you use eXtremeIO (XIO) and COPY_TO_BYTES maps, the readobject method is not invoked.

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APAR status

  • Closed as program error.

Error description

  • In an XIO environment where copyMode=COPY_TO_BYTES, XDF
    serialization is used to serializing the class. When a Java
    class implements the readObject method of the Serializable
    interface, the serialization ignores the Java readObject
    method, which might result in some transient fields not being
    properly populated when a value is deserialized. This fix
    corrects the problem so that the readObject method is invoked.
    If you encounter this issue, restart the data grid after
    you apply this fix, since it impacts the serialized data. This
    fix applies to both eXtreme Scale clients and servers.

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All WebSphere eXtreme Scale users who       *
    *                  implement XIO and set the copy mode to      *
    *                  COPY_TO_BYTES, with Java classes that       *
    *                  implement the readObject method, but do     *
    *                  implement the writeObject method.           *
    * PROBLEM DESCRIPTION: If a class implements the readObject    *
    *                      method and uses the writeObject         *
    *                      method, XDF does not revert to Java     *
    *                      serialization.                          *
    * RECOMMENDATION:                                              *
    When a Java class implements the Serializable interface method,
    readObject, but does not implement the default writeObject
    method, then Java serialization is not being used. Instead, XDF
    serialization is used, and the readObject method is not
    invoked. Since the readObject method is not invoked by the
    serializer, this behavior usually results in some fields not
    being correctly populated during deserialization.

Problem conclusion

  • The code was fixed to consider situations where only the
    readObject is defined by the class.

Temporary fix


APAR Information

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  • PE




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Fix information

  • Fixed component name


  • Fixed component ID


Applicable component levels

  • R860 PSY


Document information

More support for: WebSphere eXtreme Scale

Software version: 860

Reference #: PM79151

Modified date: 17 June 2013

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