Question

I am getting java:105: error: illegal character: \29
}

I am writing a program where the user can click a right/left/up/down button and move a “ball” on a screen.

I can’t figure out what I am doing wrong. Can someone please help me with this?

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

public class Lab2a extends JFrame {

Lab2a(){
    setTitle("Lab 1b - Application #2");
    Lab2Panel p = new Lab2Panel();
    add(p);
}

public static void main(String[] args){

    Lab2 frame = new Lab2();
    frame.setTitle("Lab2 Application # 1");
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(600, 400);
    frame.setVisible(true);
    }

}

class Lab2Panel extends JPanel{
Lab2Button canvas = new Lab2Button();
JPanel panel = new JPanel();

Lab2Panel () {

    setLayout(new BorderLayout());

    JButton leftButton = new JButton("left");
    JButton rightButton = new JButton("right");
    JButton upButton = new JButton("up");
    JButton downButton = new JButton("down");

    panel.add(leftButton);
    panel.add(rightButton);
    panel.add(upButton);
    panel.add(downButton);

    this.add(canvas, BorderLayout.CENTER);
    this.add(panel, BorderLayout.SOUTH);

    leftButton.addActionListener(new LeftListener(canvas));
    rightButton.addActionListener(new RightListener(canvas));
    upButton.addActionListener(new UpListener(canvas));
    downButton.addActionListener(new DownListener(canvas));
}


}

class Lab2Button extends JPanel {
int radius = 5;
int x = -1;
int y = -1;

protected void paintComponent(Graphics g){
    if (x<0 || y<0) {
        x = getWidth() / 2 - radius;
        y = getHeight() / 2 - radius;
    }
    super.paintComponent(g);
    g.drawOval(x,y, 2 * radius, 2 * radius);

}

        public void moveLeft(){

            x -= 5;
            this.repaint();
        }

        public void moveRight(){

            x += 5;
            this.repaint();
        }

        public void moveUp(){
            y += 5;
            this.repaint();
        }

        public void moveDown(){
            y -= 5;
            this.repaint();
        }


}

class LeftListener implements ActionListener{
    private Lab2Button canvas;

    LeftListener(Lab2Button canvas) {
     this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
     canvas.moveLeft();
    }
}

Sorry about that 105 is the line above this one.

class RightListener implements ActionListener{
    private Lab2Button canvas;

    RightListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
      canvas.moveRight();
    }
}


class UpListener implements ActionListener{
    private Lab2Button canvas;

    UpListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
        canvas.moveUp();
    }
}



class DownListener implements ActionListener{
    private Lab2Button canvas;

    DownListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
     canvas.moveDown();
    }
}

Answer 1

So, it appears that there are a few issues, but not exactly as you’ve described.

1. Line 15 Lab2 frame = new Lab2(); presumably should be Lab2a frame = new Lab2a();, or you missed including your declaration of the Lab2 object.

2. Once problem 1 has been resolved, the code compiles fine. That means that the error is in one of 2 places.

   1. The declaration of Lab2 that you possibly excluded.

   2. The bytes of your source file, in which case the best idea would be either delete and re-paste in your code from another source (like StackOverflow), or better yet retype your code. You could improve formatting along the way 🙂