Deploying applications written in Java can sometimes be troublesome. You have to make sure that the correct Java version is installed on the target system, package your classes into Jar files and you have to start your application with a sometimes pretty cryptic command line statement. Fortunately there is another way.
Since version 1.4, Java offers the technology. It offers a mechnism to deploy java applications using a standart web server.
The application can then be downloaded, installed, configured and executed automatically all with just one click. Once the application is downloaded it is cached and can be run locally on the system without delay. If the online version changes, the updated version is downloaded automatically.
In my opinion Java Web Start is a pretty awesome technology and a great way to distribute applications. One reason why it isnt used more frequently may be that it can be a bit tricky to set up a project to be compatible with Web Start. For exmaple, Java Web Start requires you to put everything into Jar files, not only your class files but also all other resources like images, sound files or 3D models. Resources may then only be loaded using the ClassLoaders getResource/ methods instead of loading them as files from the local file system. For most resources, MT4j will now first try to load the resource from the file system and in case of a failure it will try to load from the java classpath using the getResourceAsStream() method. For deploying MT4j applications using webstart, it is also required to sign the created jar file.
There are plenty of tutorials on how to create web-start apps and signed jars (e.g. or ).

As an example, I packaged the interactive water simulation as a Java Web-Start application which you can try out here:

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