Panels don't show in JFrame using LayoutManager

Question

I've got a task for school and I'm not overly good at Java yet... I'm making a borderlayout frame wherein there will several panels including some that will swap from not-visible to visible and the other way around. For some reason nothing shows when I run the program.

Screen: http://prntscr.com/5r2s6s

public class QuizIT extends JFrame {
    public static JFrame Frame;
    public static Welkom Welkom;
    public static Vraag1 Vraag1; 
    public static Vraag2 Vraag2;
    public static Vraag3 Vraag3;
    public static Vraag4 Vraag4;
    public static Vraag5 Vraag5;
    public static Vraag6 Vraag6;
    public static Punten Punten;
    public static Uitleg Uitleg;


public static void main(String[] args){

    // Frame Eigenschappen
    Frame = new JFrame();
    Frame.setSize(500, 500);
    Frame.setLocation(0, 0);
    Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Frame.setTitle("QuizIT | Naesen Technologies");
    Frame.setVisible(true);

}

public QuizIT(){
    // Layout -> BorderLayout
    setLayout(new BorderLayout());

    // Initialiseren Klassen
    Welkom = new Welkom();
    Uitleg = new Uitleg();
    Vraag1 = new Vraag1();
    Vraag2 = new Vraag2();
    Vraag3 = new Vraag3();
    Vraag4 = new Vraag4();
    Vraag5 = new Vraag5();
    Vraag6 = new Vraag6();
    Punten = new Punten();

    // Panel -> Frame
    Frame.add(Welkom, BorderLayout.CENTER);
    Frame.add(Uitleg, BorderLayout.NORTH);
    Frame.add(Vraag1, BorderLayout.CENTER);
    Frame.add(Vraag2, BorderLayout.CENTER);
    Frame.add(Vraag3, BorderLayout.CENTER);
    Frame.add(Vraag4, BorderLayout.CENTER);
    Frame.add(Vraag5, BorderLayout.CENTER);
    Frame.add(Vraag6, BorderLayout.CENTER);        
    Frame.add(Punten, BorderLayout.SOUTH);

    // Layout -> Bounds
    Uitleg.setBounds(0,0,500,100);
    Welkom.setBounds(0,100,500,300);
    Vraag1.setBounds(0,100,500,300);
    Vraag2.setBounds(0,100,500,300);
    Vraag3.setBounds(0,100,500,300);
    Vraag4.setBounds(0,100,500,300);
    Vraag5.setBounds(0,100,500,300);
    Vraag6.setBounds(0,100,500,300);
    Punten.setBounds(0,400,500,100);

    Uitleg.setBackground(Color.YELLOW);
    Welkom.setBackground(Color.YELLOW);

    // Visibility
    Welkom.setVisible(true); 
    Uitleg.setVisible(true);  
    Vraag1.setVisible(false);
    Vraag2.setVisible(false);
    Vraag3.setVisible(false);
    Vraag4.setVisible(false);
    Vraag5.setVisible(false);
    Vraag6.setVisible(false);
    Punten.setVisible(true);
}
}

Answer 1

It might be that that the constructor is being invoked first when the program starts. and after that the main method. That might be why it only loads the window but not any components.

You could try replacing constructor with a method instad and invoke the method on the last line in the main method.

This code worked fine. just replace what i wrote in the method with your code!

public static void main(String[] args){

// Frame Eigenschappen
Frame = new JFrame();
Frame.setSize(500, 500);
Frame.setLocation(0, 0);
Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Frame.setTitle("QuizIT | Naesen Technologies");
Frame.setVisible(true);
methodQuizIT();

}

public static void methodQuizIT(){
 NOW THIS CODE EXECUTES :)

} }