question: private void readObject ( ObjectInputStream in ) throws IOException , ClassNotFoundException { in . defaultReadObject ( ) ; registrarID = new ServiceID ( in ) ; if ( server == null ) { throw new InvalidObjectException ( "null server" ) ; } }
target:  Reads the default serializable field value for this instance, followed by the registrar's service ID encoded as specified by the ServiceID.writeBytes method.  Verifies that the deserialized registrar reference is non-null.