Presented below is an example for catching button click event in Swing.

Java Code:
public class TestEventSwing extends JApplet implements ActionListener {
   JButton b1, b2;
   JTextField t1;

   public void init() {
     setLayout(new FlowLayout());
     t1 = new JTextField(30);
     b1 = new JButton("Output");
     add(b1); add(t1);
     b2 = new JButton("Fire event 1st button");
     add(b2);

     b1.addActionListener(this);
     b2.addActionListener(this);
     }

   public void actionPerformed(ActionEvent e) {
     if (e.getSource() == b1) {
       t1.setText("first button clicked");
       }
     if (e.getSource() == b2) {
       //  from the b2 button, we trigger a click on the b1 button.
       //  As an added bonus, a visual effect on b1 is visible!
       b1.doClick();
       }
     }
}