Question

I have a JFrame, where a database connection is established immediately. This connection takes up to 2 seconds, meanwhile I want to show a message (or another JFrame). After the connection is established, the message should disappear.

I have a bad example, does anybody have a better idea?

public class Main extends JFrame {

    View v = new View();
    static JFrame loader = new JFrame();
    static JLabel loading = new JLabel("Loading");

    public Main() {
        this.add(v);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setExtendedState(this.getExtendedState() | JFrame.MAXIMIZED_BOTH);
        this.setBounds(100, 50, 800, 500);

        loader.setBounds(500, 300, 100, 100);
        loader.setVisible(true);
        loader.add(loading);
    }

    public static void main(String[] args) {
        Main m = new Main();
        if (DB.INSTANCE.connect()) {
            m.setVisible(true);
            loader.setVisible(false);
        } else {
            loading.setText("DB ERROR");
        }
    }
}

Answer 1

If the task is to create a splash dialog (a frame shown during the application startup while some initialisation work is being done), here is a tutorial on how to do it with Swing’s SplashScreen: http://docs.oracle.com/javase/tutorial/uiswing/misc/splashscreen.html.