Question

I started a new project, all the code is right (I think) and no window is appearing. There are no compilation errors, whenever I run the program nothing happens.

import javax.swing.*;
import java.awt.*;

public class Frame extends JFrame{

    public static String title = "Tower Defense";  
    public static Dimension size = new Dimension(700, 550);  

    public static void main(String args[]){ 

        Frame frame = new Frame(); 
    }

    public Frame()  { 

        setTitle(title);
        setSize(size);
        setResizable(false);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void init(){

        setVisible(true);
    }
}

Answer 1

You never call init() method. How can your frame be visible?

Just change your main method to:

public static void main(String args[]){ 

    Frame frame = new Frame(); 
    frame.init();
}