Question

I am currently building an address book. I am storing each entry into the address book as an object. My problem is that I cannot figure out how to get any specific variable from an object and display it. Such as the firstName for example. It’s supposed to write the variables to a file which will be loaded into the array when the program is started again.

        class ExitListener implements ActionListener{
    public void actionPerformed(ActionEvent e){
        try {
            PrintWriter output = new PrintWriter(FILE);
            ListIterator it1 = set.listIterator();
            while (it1.hasNext()){


            }
            output.flush();
            output.close();


        } catch (FileNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        System.exit(0);
    }
}

Answer 1

I’m going to have to apply my psychic debugging powers here, as you haven’t presented any code. My guess is that you’ve got a variable like this:

LinkedList list = new LinkedList();
list.add(new Person());
...
Object fetched = list.getFirst();
// Problems...

If you use generics, this becomes:

// Or use an interface type, of course
LinkedList<Person> list = new LinkedList<Person>();
list.add(new Person());
...
Person fetched = list.getFirst();
System.out.println(person.getFirstName()); // Hooray!