In order to understand API:s better I prefer to add the sources to my debugger. So for Vaadin 6.2.5 I downloaded them from http://dev.vaadin.com/svn/releases/6.2.5/
However, the sources doesn’t seem to match the JAR file, at least my debugger is confused. How do I find a matching pair?
I had the same question, but the answer was too obvious. The source code is actually in the JAR with the .class files, so there’s nothing special you need to do. In Eclipse, you can just step into Vaadin code, and for client-side code (like VButton…) you can do the same by setting breakpoints (like select the class name on the import statement where VButton is located and press F3 (Open Declaration) on Eclipse for Windows).