Here is a sample and easy tutorial to make a JProgressBar do its work i.e. keep loading. The javax.swing.Timer class allows you to do so.
import javax.swing.*;NimbusLookAndFeel: I used the NimbusLookAndFeel because it is my choice personally. Alternatively, you can just leave that if you don't want to switch from the default MetalLookAndFeel.
import java.awt.*;
import java.awt.event.*;
class JProgressBarTimer extends JFrame
{
JProgressBar jp;
Timer t;
int i=0;
public JProgressBarTimer()
{
try
{
UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
}catch(Exception e){}
setTitle("JProgressBar Timer Demo");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new GridBagLayout());
setLocationRelativeTo(null);
setVisible(true);
// Create a progress bar
jp=new JProgressBar();
// Paint the percent complete on progress bar
jp.setStringPainted(true);
// Set a size (optional)
jp.setPreferredSize(new Dimension(500,30));
// Start at 0
jp.setMinimum(0);
// End at 1000
jp.setMaximum(1000);
// Create a timer that executes for every 2 millisec
t=new Timer(2,new ActionListener(){
public void actionPerformed(ActionEvent ae)
{
if(i==1000)
i=0;
jp.setValue(i++);
}
});
// Start the timer
t.start();
add(jp);
pack();
}
public static void main(String args[])
{
new JProgressBarTimer();
}
}