java.lang.reflect.InvocationTargetException when I'm loading a self signed Jar in a local webpage

Question

I have a very simple Test program that just opens up a JFrame and I want to open it in browser. I know I have to self sign it to open it but it throws just this error:

java.lang.reflect.InvocationTargetException

I have signed the jar with the JARMAKER

My HTML to load the jar:

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
  <head>
  </head>
  <body>
    <p>Inhalt der Webseite</p>

    <applet code=Simple_Frame.class
        archive="Simple_Frame2.jar"
        width="120" height="120">
</applet>
  </body>
</html>

The simple Test program:

    import java.applet.Applet;
import java.awt.*;

/**
 * Created by Flex on 22.10.14.
 */
public class Start extends Applet{

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                Simple_Frame ex = new Simple_Frame();
                ex.setVisible(true);
            }
        });
    }
}


import javax.swing.JFrame;

public class Simple_Frame extends JFrame {

    public Simple_Frame() {

        setTitle("Simple example");
        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
}

How can I open a Jar in a webpage on my localhost to test it without that error and what does this error mean?

1) Why code an applet? If it is due to the teacher specifying it, please refer them to [Why CS teachers should **stop** teaching Java applets](http://programmers.blogoverflow.com/2013/05/why-cs-teachers-should-stop-teaching-java-applets/). 2) Why use AWT? See [this answer](http://stackoverflow.com/questions/6255106/java-gui-listeners-without-awt/6255978#6255978) for many good reasons to abandon AWT using components in favor of Swing. 3) That HTML is invalid. It declares itself as HTML 4.01, but the `applet` element was deprecated by then. — Andrew Thompson, Oct 22 '14 at 23:11

score 1 · Answer 1 · answered Oct 22 '14 at 23:09

<applet code=Simple_Frame.class
    archive="Simple_Frame2.jar"
    width="120" height="120">

The first thing that jumps out at me, is that Simple_Frame is not an applet. The Start class is though.

<applet code=Start
    archive="Simple_Frame2.jar"
    width="120" height="120">

Another tip is that InvocationTargetException is usually a wrapper for another more specific exception. Always copy/paste the full error and exception output!

java.lang.reflect.InvocationTargetException when I'm loading a self signed Jar in a local webpage

1 Answers1