Java EE (Java Enterprise Edition) General Discussion

I have recently started using XMLEncoder and XMLDecoder to perform Java Bean to XML Serialization and Deserialization. It seems to break when multiple threads are using XMLEncoder, even if each Thread is using a separate instance of XMLEncoder. I was initially seeing NullPointer exception and after obtaining a fix for that IBM Support, we are seeing various other exceptions like this.

java.lang.IllegalAccessException: Can not call newInstance() on the Class for java.lang.Class

java.lang.Exception: discarding statement XMLEncoder0.writeObject(TestObject0);
java.lang.Exception: discarding statement XMLEncoder0.writeObject(TestObject0);
at java.beans.XMLEncoder.writeStatement(XMLEncoder.java:352)
at java.beans.XMLEncoder.writeObject(XMLEncoder.java:266)
at test.XMLEncoderIssue.run(XMLEncoderIssue.java:59)
at java.lang.Thread.run(Thread.java:570)
Caused by: java.lang.RuntimeException: failed to evaluate: <unbound>=Class.new();

java.lang.ArrayIndexOutOfBoundsException: 0
at java.beans.ObjectHandler.dequeueResult(XMLDecoder.java:285)
at java.beans.XMLDecoder.readObject(XMLDecoder.java:163)
at test.XMLEncoderIssue.run(XMLEncoderIssue.java:75)
at java.lang.Thread.run(Thread.java:570)

What am i missing here?