Welcome to the Joint-Venture Blog from Fabio Cortesi and Stefan Jäger.
Sometimes, it’s very useful to watch the source code of a class file. But for this comfort, it’s necessary to download the source files and attach them in Eclipse. With the most important libraries, it make sense to spend time with downloading sources. But not with all rarely used libraries. A simple solution is the use of JadClipse. JadClipse decompiles class files with the help of the Jad Decompiler on the fly. There is no need for any source any more (of course, there are the usual limitations with decompilation).
Just download it and install it like described on the homepage (you also need to download the Jad Decompiler executable from the Jad website).