Java swing provides a Timer class to cause an action at a pre-defined rate. For instance, you could have a label that blinks at a pre-defined rate. The class has lot of practical usage.

The constructor takes Timer (int delay, ActionListener listener) as its parameter.

It has a method setCoalesce (boolean) that takes care of multiple pendingActionEvent firings:

 import javax.swing.*;import java.awt.event.*;import java.awt.*;class Time extends JFrame implements ActionListener{        JLabel l;        Time()        {               Container c=getContentPane();               c.setLayout(null);               l =new JLabel("Blink");               l.setBounds(50,50,40,40);               c.add(l);               Timer t=new Timer(500,this);//               t.setCoalesce(true);               t.start();        }        public void actionPerformed(ActionEvent e)        {                if(l.isVisible())                       l.setVisible(false);                 else                        l.setVisible(true);        }        static void main(String[]arr)throws Exception        {                Time t=new Time ();                t.setSize(200,200);                t.setVisible(true);        }}