question: public ObjectOutputStream . PutField putFields ( ) throws IOException { if ( curPut == null ) { SerialCallbackContext ctx = curContext ; if ( ctx == null ) { throw new NotActiveException ( "not in call to writeObject" ) ; } Object curObj = ctx . getObj ( ) ; ObjectStreamClass curDesc = ctx . getDesc ( ) ; curPut = new PutFieldImpl ( curDesc ) ; } return curPut ; }
target:  Retrieve the object used to buffer persistent fields to be written to the stream.  The fields will be written to the stream when writeFields method is called.