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javahtmlswingjappletimageicon

GetImage with JApplet

I have the following runnable code:

import java.awt.Graphics;

import javax.swing.ImageIcon;
import javax.swing.JApplet;
import javax.swing.JPanel;


public class Main extends JApplet{
    public static Main instance;
    public static ImageIcon getImage(String fname){
        return new ImageIcon(instance.getImage(instance.getDocumentBase(),fname));
    }
    public void init(){
        instance = this;
        @SuppressWarnings("serial")
        JPanel p = new JPanel(){
            ImageIcon img = getImage("YES.png");
            public void paintComponent(Graphics g){
                super.paintComponent(g);
                if(img != null)
                g.drawImage(img.getImage(),0,0,getWidth(),getHeight(),null);
            }
        };
        this.setContentPane(p);
    }
}

When I run this in eclipse it works. But when I run it on google chrome with the following html document:

<html>
<head>
    <title>VResponse</title>
    <style type="text/css">
        body{
            background-color:white;
            padding:1%;
        }
    </style>
</head>
<body>
<div>
<applet code="Main.class" width="800" height="600" />
</div>
</body>
</html>

I get the following null pointer exception.:

java.lang.NullPointerException
    at sun.awt.SunToolkit.getImageFromHash(Unknown Source)
    at sun.awt.SunToolkit.getImage(Unknown Source)
    at Main.getImage(Main.java:15)
    at Main$1.<init>(Main.java:21)
    at Main.init(Main.java:20)
    at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter.init(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

How do I fix?

http://vickysoderlund.atspace.cc/ /---= webpage with errored japplet on it

You should beable to download the entire folder here: https://drive.google.com/file/d/0B0ng1kJkou-lcUlmWk91bEVXX28/edit?usp=sharing

And SRC code is here: https://drive.google.com/file/d/0B0ng1kJkou-lYXRERWFnU1czX0k/edit?usp=sharing

Solution

  • The problem had to do with security. When I signed the Applet, and gave it a good permissions node in the manifest it got rid of the error.

    I added the following to the manifest:

    Permissions: all-permissions
Codebase: *.hobogames.atspace.cc
Application-Name: GreenCube

    I signed it in the command prompt using the following commands:

    cd homeDirectory
keytool -genkey -alias alias -keystore .keystore

cd directoryOfJar
jarsigner jar-file alias

    Where alias is usually your name.

    This solved some security issues, and allowed me to load the image.