Sometimes it is useful to know if Swing is installed in a Java environmentor not, especially if you are dealing with browsers. You can simply try tocreate a Swing component, as in:

 try {    javax.swing.JButton jBtn = new javax.swing.JButton
("a button");    System.out.println("Swing is installed");     jBtn = null;}catch(NoClassDefFoundError e) {    System.out.println("Swing is not here, 
you must download or installit");    }