Is this the proper way to save an object?

I need to implement a save/load for a board game. The class that calculates everything is called LinkPuzzle, which consists of two variables indicating length and width, and a two dimensional array.

There are so many ways to save things in java that I'm confused as to which one to use, of course, so far all of my attempts have thrown errors. This one says "uncompilable source code". It's located in the GUI.

I'm trying to save the object "puzzle", I've attached a implements serializable to the non-GUI part. It's not working though =/

Code:

---

JButton loadButton = new JButton("Load");
                loadButton.addActionListener(new ActionListener() {
                       
                        @Override
                        public void actionPerformed(ActionEvent arg0) throws IOException, ClassNotFoundException {

                            ObjectInputStream input = new ObjectInputStream(new FileInputStream("array.dat"));
                            LinkPuzzle puzzle = (LinkPuzzle)(input.readObject());

                            //adjust GUI according to puzzle

                            input.close();
                    }

                       
                });
                JButton saveButton = new JButton("Save");
                saveButton.addActionListener(new ActionListener() {
                       
                        @Override
                        public void actionPerformed(ActionEvent arg0) throws IOException, ClassNotFoundException {
                            ObjectOutputStream output = new    ObjectOutputStream(new FileOutputStream("array.dat",true));
                            output.writeObject(puzzle);
                            output.close();
                    }
                });

---

Does LinkPuzzle extend Object?

Doesn't every class in Java extend Object even when not explicitly stated?

1. Does LinkPuzzle implement Serializable?

2. Take a look at java.util.prefs.Preferences.

db

I thought every class automatically extended Object.

Do such replies mean that my code is correct and that the error lies in some other technicality? I've implemented serializable according to an example.

LinkPuzzle implements java.io.Serializable{
...
}

and in the GUI I just have what I posted above.

LinkPuzzle(){
int m;
int n;
int[][] cells;
}

My constructor.

Maybe it has something to do with my file? I just wrote a text document, called it array.dat, and placed it in the same folder with my .java files.

What does the error "source code uncompilable" mean anyway?

How are you compiling this?
Because "uncompilable source code" is pretty menaningless.

Introducing Persistence

have a look here