@Override
    public void printStackTrace() {
        super.printStackTrace();
        if (nestedThrowable != null) {
            nestedThrowable.printStackTrace();
        }
    }
Thrown when attempting to create a user that already exists.

@author Iain Shigeoka
xmppserver/src/main/java/org/jivesoftware/openfire/user/UserAlreadyExistsException.java