HelloJava.java

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

public class HelloJava {
    public static void main( String[] args ) {
        JFrame frame = new JFrame( "TEST!!!" );
        //JLabel label = new JLabel("Hello, Java!", JLabel.CENTER );
        frame.add(new HelloComponent());
        frame.setSize( 300, 300 );
        frame.setVisible( true );
    }
}

class HelloComponent extends JComponent {
    public void paintComponent(Graphics g) {
        g.drawString("TEST!!!", 150, 150);
    }
}