Creating and running a Java applet

Question

I thought I would try my hand at applets - I made an applet using Eclipse. It runs fine using the Run As -> Java Applet.

I read a bit about running it outside Eclipse, so I did the following:

Made a folder.
Created New -> Java Project [applet_test].
Inside the project, I created New -> Other -> Visual Swing Class -> Applet [Number1] - that created Number1.class.
Added code and ran it as a Java applet - it ran fine.
Exported the project as a JAR file (not a runnable JAR file).
Wrote HTML using TextEdit (Mac's version of Windows' Notepad). The HTML follows, below...
I put the JAR file, HTML and .class file in the folder.
In Terminal (Mac's version of Windows command prompt window), I ran Appletviewer applet_testX2.html (that's the name of my HTML).
I could see a brief flash of the application name at the top of the screen (as would any other running application).

However, the application (which should display a Jpanel with a label and a button) did NOT appear. I also tried running it from Firefox and Safari. Only the HTML code appeared.

So, what am I doing wrong? And, more importantly, how do I do it correctly?

Code follows without imports statements:

<html>
    <body>
        <applet code="Number1.class" archive="applet_test.jar"
            width=300
            height=300>
        </applet>
    </body>
</html>

The Java code:

public class Number1 extends JApplet {
    public Number1() {

    }

    private static final long serialVersionUID = 1L;

    @Override
    public void init() {
        try {
            EventQueue.invokeAndWait(new Runnable() {
                @Override
                public void run() {
                    initComponents();
                }
            });
        }
        catch (Exception ex) {
            ex.printStackTrace();
        }
    }
    private void initComponents() {
        setSize(320, 240);

        JPanel panel = new JPanel();
        getContentPane().add(panel, BorderLayout.CENTER);

        JLabel lblAppletTest = new JLabel("Applet test 1");
        panel.add(lblAppletTest);

        JButton btnPushIt = new JButton("Push it");
        panel.add(btnPushIt);
    }
}

Firefox source view:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <meta http-equiv="Content-Style-Type" content="text/css">
        <title></title>
        <meta name="Author" content="BT">
        <meta name="Generator" content="Cocoa HTML Writer">
        <meta name="CocoaVersion" content="1038.35">
        <style type="text/css">
            p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 16.0px Helvetica}
            p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 16.0px Helvetica; min-height: 19.0px}
        </style>
    </head>
    <body>
        <p class="p1">&lt;html&gt;</p>
        <p class="p1"><span class="Apple-converted-space"> </span>&lt;body&gt;</p>
        <p class="p1"><span class="Apple-converted-space">   </span>&lt;applet code="Number1.class" archive="applet_test.jar"</p>
        <p class="p2"><br></p>
        <p class="p1"><span class="Apple-converted-space">    </span>width=300</p>
        <p class="p1"><span class="Apple-converted-space">   </span>height=300&gt;</p>

        <p class="p1">&lt;/applet&gt;</p>
        <p class="p1">&lt;/body&gt;</p>
        <p class="p1">&lt;/html&gt;</p>
    </body>
</html>

Thanks. I did not receive any errors. The browser simply showed the HTMl text shown above. Looking at the Source view in Firefox did not indicate any oddities. I'll add it above... — headscratch
– headscratch, Commented Feb 17, 2011 at 20:55
Are you sure that there's no errors? Sometimes you have to dig to find them. What if you go into FireFox's tools java console? — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Feb 17, 2011 at 21:03
"Thought I try my hand at Applets.." Why? Unless you have a specific need for a rich client that is embedded in a web page, it would be better (and easier) to develop a JFrame baed app. that is launched using Java Web Start. I generally try to avoid applets, and that is coming from someone who has a number of applets on their site, has developed scores, and worked on hundreds. Applet are not easy. — Andrew Thompson
– Andrew Thompson, Commented Feb 18, 2011 at 6:13

Hovercraft Full Of Eels · Accepted Answer · 2011-02-17 20:54:16Z

2

My guess is that here:

<applet code="Number1.class" archive="applet_test.jar"

you're not taking packages into consideration. For instance, if the package is myPackage.vol3 then the line should read

<applet code="myPackage.vol3.Number1.class" archive="applet_test.jar"

But if this doesn't help, you'll want to extract any error messages that the browser gives you and edit your original post to show us what they are.

answered Feb 17, 2011 at 20:54

Hovercraft Full Of Eels

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10 Comments

headscratch Over a year ago

I used that default package (probably shouldn't have and may need to redo the project as I seem not able to refactor/rename the package.

Hovercraft Full Of Eels Over a year ago

see comment above. By the way, your Java code worked fine in an applet for me, and so did the html code after correcting for packages. I ran it on FireFox and Chrome.

headscratch Over a year ago

Well - first, thanks. I deleted the class and made a new class with a package. I changed the html to reflect this: applet code="com.bt.applettest.Number1.class" archive="applet_test.jar" But, it still does NOT work. I still only get the html code in the browser window. Is there a browser setting that I need to address?

Hovercraft Full Of Eels Over a year ago

where is the jar file in relation to the HTML file? Are they in the same directory? Again, if using FireFox, have you checked the Tools menu's Java Console?

headscratch Over a year ago

Solved Need to put the html file in the project folded "INSIDE" the eclipse project IDE (via File>New>File...)

|

Loopo · Accepted Answer · 2015-10-16 11:31:53Z

                 Using Appletviewer
                 ------------------

Write code of Applet.
If you installed tomcat in D:
code

-

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class MyApplet extends Applet
{
    public void init()
    {
        System.out.println("init intilize");
        GridLayout g=new GridLayout(4,6,0,0);
        setLayout(g);
        MyListener m=new MyListener();

        for(int i=1;i<=12;i++)
        {
            Button b=new Button("ok"+i);
            add(b);
            b.addActionListener(m);
        } 
    }//end of init

    public void start()
    {
        System.out.println("applet started");
    }//end of start

    public void stop()
    {
        System.out.println("applet stop");
    }//end of 

    public void paint(Graphics g)
    {
      g.drawString("Naveed",200,25);
      g.drawOval(20,30,30,20);
      System.out.println("applet paint");
    }//end of start

    public void destroy()
    {
        System.out.println("applet destroy");
    }//end of start
}

class MyListener implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        System.out.println("button clicked");
    }//end of actionPerformed
}

Now save this code in D:, not in sub folder.

First Compile it.

open the cmd

cd D:

type

`javac MyApplet.java -d classpath D:\Tomcat\common\lib\servlet.jar`

This will make a MyApplet.class file

Now make a html file.

<html>
<body>
    <applet code="Number1.class" width=30  height=300 > </applet>
</body>
</html>

Save with the name of you want let's say app.html

run the html file now.

In the cmd window

appletviewer app.html

Output will be in front of you.

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