java: cleaning / logging before shutdown

1. Use a Shutdown Hook

If you would like to shutdown some connections, restore resources, or print a log message before your program is shut down, you may use the Shutdown hook to achieve it.

public class CleanTest {
      private String name;

      public CleanTest(String name){
            this.name = name;

            Runtime.getRuntime().addShutdownHook(new Thread() {
                 public void run() {
                        Log.write("CleanTest is shutting down....");
                       //shutdown connections
                       //restore resources
                }
         });
    }
}

2. Use a Window Listener

If you are executing a java.awt.Window object such as JFrame and JDialog, you can add a java.awt.event.WindowListener to do the job.

public class CleanTest extends JFrame {
    private String name = "";
 
    public CleanTest (String name) {
        this.name = name;
        //Build your window components
     
        setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

        this.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e){
                //shutdown connections
                //restore resources
            }
        });

        pack();
        setVisible(true);
    }

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