Can't add different bottons in a single actionlistener using the windowbuilder in eclipse

I made a program using the window builder (with eclipse), but with which I can't add all the buttons in a single actionlistener and actionperformed ... I tried to add "implements ActionListener" next to public class JFrame... extends JFrame, but when I type at the end inside the actionperformed it doesn't "recognize the buttons". The problem is that if I leave the single actionlistener to each button, as the program does automatically, it doesn't store me a single char array, but it initializes it every time I press a new button. I hope I was clear, thanks.