Mine

//winkel.java    private ArrayList<Cd> cdWinkel = new ArrayList<Cd>();    private String fileName = "cd.dat";    private Cd ingelezenCd;    public void write(String fileName) {       try{           ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(fileName));           for(Object o : cdWinkel){                if(out.equals(o) == false){                   out.writeObject(o);                }           }           out.close();       }       catch(IOException i){           i.printStackTrace();       }    }        public void read( String fileName ) {        try{            ObjectInputStream in = new ObjectInputStream(new FileInputStream(fileName));                         while(in != null){                ingelezenCd = (Cd) in.readObject();                 cdWinkel.add(ingelezenCd);            }            in.close();        }        catch(IOException i){            i.printStackTrace();        }        catch(ClassNotFoundException c){            c.printStackTrace();        }    }//einde winkel.java//gui.java    private void performOpen() {        String fileName = "cd.dat";        winkel.read(fileName);    }    private void performSluit() {        String fileName = "cd.dat";        winkel.write(fileName);        winkel.nieuw();    }//einde//einde