this is my code. I have no clue what could be wrong with it. The error that keeps coming up is: class, interface, or enum expected. The five errors it pointed out are the 'v' in public void actionPerformed at the bottom of the code, the 'g' in the green = Integer.parseInt....., the 'b' in the blue = Integer.parseInt..... the 'r' in the repaint().. and '}' at the very end of the code... anyone can help?

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


public class UpdatedColorApplet extends JApplet implements ActionListener {

    private JTextField txtRed = new JTextField("255", 3);
    private JTextField txtGreen = new JTextField("255", 3);
    private JTextField txtBlue = new JTextField("255", 3);
    private JButton cmdEnter = new JButton("Enter");

    private int red=255;
    private int green=255;
    private int blue=255;


    /**
     * The entry point for the applet.
     */
    public UpdatedColorApplet(){

        // get contentPane & set layout manager
        Container cp = getContentPane();
        cp.setLayout(new FlowLayout());


        // text components & labels
        cp.add(new JLabel("CPT 237 - Java - Color Class RGB Component Demonistration Applet"));
        cp.add(new JLabel("Red"));
        cp.add(txtRed);
        cp.add(new JLabel("Green"));
        cp.add(txtGreen);
        cp.add(new JLabel("Blue"));
        cp.add(txtBlue);
        cp.add(new NewLabel());

        // add button and set up handler
        cp.add(cmdEnter);
        cmdEnter.addActionListener(this);

}

    public static void main(String[] args) {
        UpdatedColorApplet frame = new UpdatedColorApplet();
        frame.setSize(250, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
}
}

    class NewLabel extends JLabel {
        protected void paintComponent(Graphics g) {

        super.paintComponent(g);

        // draw the large rectangle
        g.setColor(new Color(red, green, blue));
        g.fillRect(100, 100, 200, 150);

        // draw the red component rectangle
        g.setColor(new Color(red, 0, 0));
        g.fillRect(120, 120, 40, 100);

        // draw the green component rectangle
        g.setColor(new Color(0, green, 0));
        g.fillRect(180, 120, 40, 100);

        // draw the blue component rectangle
        g.setColor(new Color(0, 0, blue));
        g.fillRect(240, 120, 40, 100);

}
}


    public void actionPerformed(ActionEvent e) {
        // get color components
        red = Integer.parseInt(txtRed.getText());
        green = Integer.parseInt(txtGreen.getText());
        blue = Integer.parseInt(txtBlue.getText());

        // repaint the applet
        repaint();
}

Your actionPerformed method is not actually inside your class. Check your braces.

I did that and this is the code below. I'm pretty sure i got it all right but i just can't seem to find what i am missing. It's giving me 2 errors now referring to the dots in the frame.setLocation... and frame.setDefault.... saying cannot find symbol.

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


public class UpdatedColorApplet extends JApplet implements ActionListener {

    private JTextField txtRed = new JTextField("255", 3);
    private JTextField txtGreen = new JTextField("255", 3);
    private JTextField txtBlue = new JTextField("255", 3);
    private JButton cmdEnter = new JButton("Enter");

    private int red=255;
    private int green=255;
    private int blue=255;
    /**
     * The entry point for the applet.
     */
    public UpdatedColorApplet(){

        // get contentPane & set layout manager
        Container cp = getContentPane();
        cp.setLayout(new FlowLayout());


        // text components & labels
        cp.add(new JLabel("CPT 237 - Java - Color Class RGB Component Demonistration Applet"));
        cp.add(new JLabel("Red"));
        cp.add(txtRed);
        cp.add(new JLabel("Green"));
        cp.add(txtGreen);
        cp.add(new JLabel("Blue"));
        cp.add(txtBlue);
        cp.add(new NewLabel());

        // add button and set up handler
        cp.add(cmdEnter);
        cmdEnter.addActionListener(this);




}

    public static void main(String[] args) {
        UpdatedColorApplet frame = new UpdatedColorApplet();
        frame.setSize(250, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

}
    public void actionPerformed(ActionEvent e) {
                // get color components
                red = Integer.parseInt(txtRed.getText());
                green = Integer.parseInt(txtGreen.getText());
            blue = Integer.parseInt(txtBlue.getText());
}

    class NewLabel extends JLabel {
        protected void paintComponent(Graphics g) {

        super.paintComponent(g);

        // draw the large rectangle
        g.setColor(new Color(red, green, blue));
        g.fillRect(100, 100, 200, 150);

        // draw the red component rectangle
        g.setColor(new Color(red, 0, 0));
        g.fillRect(120, 120, 40, 100);

        // draw the green component rectangle
        g.setColor(new Color(0, green, 0));
        g.fillRect(180, 120, 40, 100);

        // draw the blue component rectangle
        g.setColor(new Color(0, 0, blue));
        g.fillRect(240, 120, 40, 100);

        // repaint the applet
        repaint();

}
}
}

You are extending/subclassing your class to JApplet class which doesnt have the method used by you. You need to extend JFrame to use

frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

I changed it to JFrame and when i compile there are no errors, but when i run it the error message is exception in thread main java.lang.NoSuchMethodError: main.

I changed it to JFrame and when i compile there are no errors, but when i run it the error message is exception in thread main java.lang.NoSuchMethodError: main.

Well its working fine for me. TRy to catch the exception using printStackTrace() and then tell which line you are getting exception