question: @ SuppressWarnings ( "unchecked" ) private void readObject ( java . io . ObjectInputStream s ) throws java . io . IOException , ClassNotFoundException { ObjectInputStream . GetField gf = s . readFields ( ) ; readOnly = gf . get ( "readOnly" , false ) ; Set < Principal > inputPrincs = ( Set < Principal > ) gf . get ( "principals" , null ) ; if ( inputPrincs == null ) { throw new NullPointerException ( ResourcesMgr . getString ( "invalid.null.input.s." ) ) ; } try { principals = Collections . synchronizedSet ( new SecureSet < Principal > ( this , PRINCIPAL_SET , inputPrincs ) ) ; } catch ( NullPointerException npe ) { principals = Collections . synchronizedSet ( new SecureSet < Principal > ( this , PRINCIPAL_SET ) ) ; } this . pubCredentials = Collections . synchronizedSet ( new SecureSet < Object > ( this , PUB_CREDENTIAL_SET ) ) ; this . privCredentials = Collections . synchronizedSet ( new SecureSet < Object > ( this , PRIV_CREDENTIAL_SET ) ) ; }
target:  Reads this object from a stream (i.e., deserializes it)