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  1. #1
    paulsim is offline Member
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    Default ClassCastException

    Hi

    It seems like there are thousands of people with this problem asking around on the Internet - and I don't find a decent reply.

    I am trying to create a simple applet with JButtons

    When compiling in JCreator I get the following message.

    java.lang.ClassCastException: FramedButton cannot be cast to java.applet.Applet
    at sun.applet.AppletPanel.createApplet(AppletPanel.ja va:786)
    at sun.applet.AppletPanel.runLoader(AppletPanel.java: 715)
    at sun.applet.AppletPanel.run(AppletPanel.java:369)
    at java.lang.Thread.run(Thread.java:619)

    When compiling with javax it compiles OK but does not initialise.

    I have tried many examples of simple button demo applets including the one on the java site.

    also this one which is similar but does not require gifs.


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

    public class ButtonDemo extends JFrame
    {
    protected JButton startButton, stopButton;

    // Constructor sets features of the frame, creates buttons, adds them to the frame, and
    // assigns an object to listen to them
    public ButtonDemo()
    {
    super("Button demo"); // set title bar

    setSize(400,200); // sets the size of the window

    startButton = new JButton("Start"); // create two new buttons w/labels start and stop
    stopButton = new JButton("Stop");

    startButton.setBackground(Color.green); // set backgrounds of buttons
    stopButton.setBackground(Color.red);

    Container contentPane = getContentPane();
    contentPane.setLayout(new FlowLayout()); // sets layout so objects added go from left to right
    // until fill up row and then go to next row
    contentPane.add(startButton);
    contentPane.add(stopButton);

    // create objects to listen to each button (separately):
    startButton.addActionListener(new StartButtonListener());
    stopButton.addActionListener(new StopButtonListener());
    }


    // Trivial main program associated with new window
    public static void main(String[] main){
    ButtonDemo app = new ButtonDemo(); // Create an instance of Buttons
    app.show(); // Show it on the Mac screen
    } // -- leave this out and you won't see it!

    // Listener for start button
    protected class StartButtonListener implements ActionListener{

    // print "start button" when button pushed
    public void actionPerformed(ActionEvent evt)
    {
    System.out.println("Start button");
    }
    }

    // Listener for stop button
    protected class StopButtonListener implements ActionListener{

    // print "stop button" when button pushed
    public void actionPerformed(ActionEvent evt)
    {
    System.out.println("Stop button");
    }
    }

    }

    I have read many short comments but no solutions.

    Is my Java installed correctly?

    I do have the classpath coorect to java.swing.

    Please help me - and many others.

    paulsim

  2. #2
    Eranga's Avatar
    Eranga is offline Moderator
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    Default

    First of all, I have found something on your code. I can't see that you have extend the JApplet in order to implement an applet.

  3. #3
    Norm's Avatar
    Norm is offline Moderator
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    Default

    Having trouble understanding your problem.
    When compiling in JCreator I get the following message.

    java.lang.ClassCastException: FramedButton cannot be cast to java.applet.Applet
    This looks like an execution time error message, not a compile error.
    Where is FramedButton defined? Its not in the code you posted.
    When compiling with javax
    What is the javax program? Sun's java JDK uses javac to compile java programs.

    Your code show a main() method. These are not used in Applets.

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