import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class SimpleExample extends JFrame {

    public SimpleExample() {

        setTitle("Simple example");
        setSize(500, 500);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        JButton jb = new JButton("TEST");
        jb.setBorderPainted(true);
        jb.setBounds(5, 5, 1, 1); ---> This line
        add(jb);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                SimpleExample ex = new SimpleExample();
                ex.setVisible(true);
            }
        });
    }
}

只需创建一个首选大小的简单按钮即可。该setBounds方法似乎不起作用。我要去哪里错了？