@Override
    public void printStackTrace(PrintWriter pw) {
        super.printStackTrace(pw);
        if (nestedThrowable != null) {
            nestedThrowable.printStackTrace(pw);
        }
    }
Exception used for representing that the specified node configuration is not acceptable. A
not acceptable error could occur if owner tries to leave the node without owners. A 406 error
code is returned to the user that requested the invalid operation.

@author Matt Tucker
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/NotAcceptableException.java