setLocationRelativeTo(Component)
setLocationRelativeTo(fenster)
setLocationRelativeTo(getParent())
Hauptfenster fenster = new Hauptfenster("titel");
import javax.swing.*;
public class Main {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final JFrame f = new JFrame();
f.setSize(500, 500);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
final JDialog d = new JDialog(f);
d.setSize(200, 200);
d.setLocationRelativeTo(f);
d.setVisible(true);
}
});
}
}