import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.BorderLayout;

public class TestGui {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Test GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);
        JLabel label = new JLabel("GUI is working!", JLabel.CENTER);
        frame.getContentPane().add(label, BorderLayout.CENTER);
        frame.setVisible(true);
    }
}