Integrate JAR files into your Windows desktop
Dieter Krachtus just sent me a link to a project he's working on, a shell extension which allows you to treat JAR files as executable programs under Windows. Now, double-clicking on a JAR file has long caused it to be launched under "java -jar", but with the generic "Java document" icon it doesn't exactly scream "executable program". I'm not sure how many people even know that you can double-click on a JAR to launch it, and between that and the generic icon that probably explains why I've never seen a Java program which took advantage of that ability.
With the ability to embed multiple resolutions / color depths of icons directly into your JAR files, as well as Ant integration and a GUI, this looks like a nifty little project. It's currently limited by the fact that it has to be installed on the end-user's system to function, but... what if this sort of capability were integrated directly into the JRE? Is that something you would find useful?
It's also worth mentioning that, as a Mac user, I'm used to being able to "install" most applications by simply dragging them to my Applications folder or other convenient location, and "uninstall" them by dragging them to the trash. JAR files potentially represent the same capability offered to users of other platforms -- just download the JAR file, and that is the program, with no need to install it before using it or uninstall it when you're done with it. Just double-click on it to run it, and if you decide you don't want it anymore you merely need to delete it. I think there's quite a bit of merit to this idea.
Update: Sorry, I should have explicitly stated that Dieter does not work for Sun and this is not a Sun project -- it's just something I thought was neat. I should also mention that most of the credit goes to Chris Deckers, the project lead.