How can I fix the Java error: myClass is not abstract and does not override abstract method?

Question

I'm very new to Java and being the GUI obsessed freak I am, got drawn to Swing. I have not much experience with Java (really basic knowledge) and I've started making a game. I want to use Swing for it and have started with some basic code for the login/register system under the guidance of a website.

However, they don't tell me how to make a button run a command, so, I scoured the internet and found ActionListener but I'm not sure how to use it. I've tried implementing it in my code but I get an error for it. I'm don't know what is wrong, I can't find anything useful on how to fix this error:

Apiary is not abstract and does not override abstract method
actionPerformed(java.awt.event.ActionListener) in
java.awt.event.ActionListener

Here is my code:

import javax.swing.*;
import java.awt.event.ActionListener;

public class Apiary implements ActionListener {   
    public static void main(String[]args) {
        JFrame frame = new JFrame("Apiary");
        frame.setSize(350, 150);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

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

        frame.setVisible(true);
        panel.addActionListener(placeComponents);
    }    
    private static void placeComponents(JPanel panel) {
        panel.setLayout(null);

        JLabel usernameLabel = new JLabel("Username");
        usernameLabel.setBounds(10,20,80,25);
        panel.add(usernameLabel);

        JTextField userText = new JTextField(20);
        userText.setBounds(100,20,165,25);
        panel.add(userText);

         JLabel passwordLabel = new JLabel("Password");
        passwordLabel.setBounds(10,50,80,25);
        panel.add(passwordLabel);

        JPasswordField passwordText = new JPasswordField(20);
        passwordText.setBounds(100,50,165,25);
        panel.add(passwordText);

        JButton loginButton = new JButton("Login");
        loginButton.setBounds(10, 80, 80, 25);
        panel.add(loginButton);
    }
}

Answer 1

How can I fix the Java error: myClass is not abstract and does not override abstract method?

Add an actionPerformed(ActionEvent) method. Be sure to add the @Override notation. See other changes as noted in this working example.

import javax.swing.*;
import java.awt.event.*;

public class Apiary implements ActionListener {   

    private static void placeComponents(JPanel panel) {
        panel.setLayout(null);

        JLabel usernameLabel = new JLabel("Username");
        usernameLabel.setBounds(10,20,80,25);
        panel.add(usernameLabel);

        JTextField userText = new JTextField(20);
        userText.setBounds(100,20,165,25);
        panel.add(userText);

         JLabel passwordLabel = new JLabel("Password");
        passwordLabel.setBounds(10,50,80,25);
        panel.add(passwordLabel);

        JPasswordField passwordText = new JPasswordField(20);
        passwordText.setBounds(100,50,165,25);
        panel.add(passwordText);

        JButton loginButton = new JButton("Login");
        loginButton.setBounds(10, 80, 80, 25);
        panel.add(loginButton);
        Apiary apiary = new Apiary();
        loginButton.addActionListener(apiary);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("ToDo!");
    }

    public static void main(String[]args) {
        JFrame frame = new JFrame("Apiary");
        frame.setSize(350, 150);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

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

        frame.setVisible(true);
    }
}

General tips:

1. For a log-in, I'd recommend using a modal JDialog or a JOptionPane instead of a JFrame to display it. See The Use of Multiple JFrames, Good/Bad Practice?
2. Java GUIs have to work on different OS', screen size, screen resolution etc. using different PLAFs in different locales. As such, they are not conducive to pixel perfect layout. Instead use layout managers, or combinations of them along with layout padding and borders for white space.