import java.awt.Color;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;

public class MainWindow extends JFrame {
    JPanel panel1;

    public MainWindow() {
        this.panel1 = new JPanel();
        this.panel1.setBounds(5, 5, 200, 100);
        this.panel1.setBorder(new LineBorder(Color.BLUE));

        this.setLayout(null);
        this.add(this.panel1);
        this.setTitle("App");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(215, 135);
        this.setVisible(true);
    }
    
}