Simple JFrame sample

MyFrame.java

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextArea;

public class MyFrame {
    public static void main(String[] args) {
        JFrame f = new JFrame("test");
        JTextArea ta = new JTextArea();
        f.add(ta);
        JButton b = new JButton("Hello");
        b.addActionListener(al -> ta.append("Hello!!\n"));
        f.add(BorderLayout.NORTH, b);
        
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(500, 400);
        f.setVisible(true);
    }
}