Checking if JTextField not empty

Question

I am trying to create example for GUI its take the name from user in JTextFiled and appear message for user with their name that was entered in JtextField, now I wanna make method check if the user enter on the button without enter anything, I trying to use this method in ActionListener but I see error in editor, while when I use it outside the ActionListener I see it's works! , please see the attachment picture

    public class Example01 extends JFrame {

    public JTextField text;
    public Example01() {
        setTitle("Example 01");
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        panel.setBorder(BorderFactory.createEmptyBorder(50, 50, 50, 50));
        JLabel label = new JLabel("Enter Your Name : ");
        text = new JTextField();
        text.setSize(30, 10);
        JButton btn1 = new JButton("Enter");

        btn1.addActionListener(new ActionListener() {

        if (text.getText().equals("")) {
            JOptionPane.showMessageDialog(rootPane, "Please enter anything");
        }

            @Override
            public void actionPerformed(ActionEvent e) {
                JOptionPane.showMessageDialog(rootPane, "Hello : " + text.getText());
            }
        });
        panel.add(label);
        panel.add(Box.createRigidArea(new Dimension(0, 20)));
        panel.add(text);
        panel.add(Box.createRigidArea(new Dimension(0, 20)));
        panel.add(btn1);

        add(panel);
        setVisible(true);
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

}

error message

Edit
the problem is because I put code outside of an executable context "a method"

Answer 1

Take...

if (text.getText().equals("")) {
    JOptionPane.showMessageDialog(rootPane, "Please enter anything");
}

and put it inside you actionPerformed method...

btn1.addActionListener(new ActionListener() {

    @Override
    public void actionPerformed(ActionEvent e) {
        if (text.getText().equals("")) {
            JOptionPane.showMessageDialog(rootPane, "Please enter anything");
        }
        JOptionPane.showMessageDialog(rootPane, "Hello : " + text.getText());
    }
});