Serializing and deserializing ArrayList of objects

Question

I have an arrayList of objects public ArrayList<Brick> bricks; defined later in the constructor bricks = new ArrayList<Brick>(); . And then used in paintComponent method:

public void paintComponent(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;
    super.paintComponent(g);
     for(Brick b: bricks){
        b.draw(g2d, b.type);
     }

    Toolkit.getDefaultToolkit().sync();
}

After adding bunch of objects I'm using serialize method :

    public void serialize(ArrayList<Brick> al){
        try{
            FileOutputStream fos= new FileOutputStream("levels/level1");
            ObjectOutputStream oos= new ObjectOutputStream(fos);
            oos.writeObject(al);
            oos.close();
            fos.close();
          }catch(IOException ioe){
               ioe.printStackTrace();
          }
    }

to save it to file (Although Eclipse throws some warnings the file is being created). However I'm having problem deserializing it (list is not being loaded):

public void deserialize(){
    try
    {
        FileInputStream fis = new FileInputStream("levels/level1");
        ObjectInputStream ois = new ObjectInputStream(fis);
        ArrayList<Brick> readObject = (ArrayList<Brick>) ois.readObject();
        bricks = readObject;
        ois.close();
        fis.close();
     }catch(IOException ioe){
         ioe.printStackTrace();
         return;
      }catch(ClassNotFoundException c){
         System.out.println("Class not found");
         c.printStackTrace();
         return;
      }
}

Am I doing something wrong ?

your `Brick` class have to implement `Serialaisable` interface. — catch23, Feb 27 '16 at 22:06
it does now. There are no warnings while saving now but still can't load a file. — JohnnyGat, Feb 27 '16 at 22:17
Yes, a NullPointerException at draw() method probably because list is not loaded and objects can't be drawn — JohnnyGat, Feb 27 '16 at 22:41
At the very least, your static `bricks` should be instantiated on creation, cleared, and added-to, not assigned with =. That would at least avoid the NPE. — Andrew Regan, Feb 27 '16 at 23:08

Serializing and deserializing ArrayList of objects

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