Improving legacy Java Applets both Performance and Appearance

Question

I have a rather large legacy Java Applet that has several problems:

1. It looks like shi$%#$
2. It loads up slowly
3. It hangs on some browsers occasionally even with the latest JRE

Because Java Applets have kind of gone the way of the dodo bird I can't find any recent reliable information on how to mitigate these problems.

That being said I don't want to replace the applet with new technology as that will be to much work at this time.

Are there any tips, tricks, or references that people have on this problem?

Answer 1

1) It looks like shi$%#$

UI matter. Consider changing Swing look'n'feel.

2) It loads up slowly

Can be caused by large file size and/or slow network. How much has the client to download before running the applet? Isn't the applet JAR file unnecessarily large? E.g. source files included? Too large images included? Too many unused classes and libraries included? Proguard may help a lot in minimizing the JAR file size.

This can also be caused by inefficient code. Is it written with memory and CPU efficiency in mind? Run a Profiler to see it and improve accordingly.

3) It hangs on some browsers occasionally even with the latest JRE

Browser matter. True, reliably deploying an applet is horrible. You may want to consider to use the Deployment Toolkit Script for this. The JavaScript will determine the browser used and its capabilities and take actions accordingly. It's as easy as following example taken from the aforelinked site:

<script src="http://www.java.com/js/deployJava.js"&gt;&lt;/script&gt;
<script>
    var attributes = {codebase:'http://java.sun.com/products/plugin/1.5.0/demos/jfc/Java2D',
                      code:'java2d.Java2DemoApplet.class',
                      archive:'Java2Demo.jar',
                      width:710, height:540} ;
    var parameters = {fontSize:16} ;
    var version = '1.6' ;
    deployJava.runApplet(attributes, parameters, version);
</script>