TryFrame.java

import javax.swing.*;

public class TryFrame
{
    public static void main(String[] argv)
    {
        TFrame f = new TFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.show();
    }
}

class TFrame extends JFrame
{
    public TFrame()
    {
        setSize(300,200);
        setTitle("This is a test");
    }
}