import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("My title!");
        frame.setVisible(true);
        frame.setSize(300, 150);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        frame.add(panel);

        JLabel label = new JLabel("my label");
        panel.add(label);

        JButton button = new JButton("my button");
        panel.add(button);
    }
}