传递对象以摆动GUI

Question

I have 5-6 GUIs(seperate classes) one opens another according to their functionality, every GUI takes an object inside, I pass the final Object in a flight booking system like this to my GUI when a JButton "Book" is clicked from the seat selection menu in Book_GUI.java

Passenger_GUI frameP = new Passenger_GUI(eco.seats[x][z].getMyPassenger());
frameP.setVisible(true);    
eco.seats[x][z].setBooked(true);

in Passenger_GUI.java I have:

        private Passenger passenger_GUI;

later in Constructor without initializing passenger_GUI I assign the input Passenger Object to it:

public Passenger_GUI(Passenger myPassenger) {
    passenger_GUI = myPassenger;

Everything works no errors... I have 2 questions, do I have to initialize first passenger_GUI and then make the assigment or is it not necessary? Second important question; the changes I make in the Passenger_GU to object myPassenger( eco.seats[x][z].myPassenger ), will they be saved in the previous GUI Book_GUI.java I think not because the Passenger_GUI class does not have a return value... or am I wrong?How can I make the changes I apply on an Object stable and be used for the future in Book_GUI.java ?(previous GUI) Thank you for your time!

Here full classes: http://www.copypastecode.com/643018/ http://www.copypastecode.com/643022/

Answer 1

1. No, you can just initialize passenger_GUI in your constructor.
2. The changes should persist. Since you're passing an Object and not a primitive to your Passenger_GUI constructor, Java actually passes a reference to that Passenger object. Your Passenger_GUI.passenger_GUI field should refer to the same object (and indeed, the same location in memory) as eco.seats[x][z].getMyPassenger() , so any changes made to that object from within Passenger_GUI should also be visible from Book_GUI .