JDiff is a Javadoc doclet which emits an HTML report of all the packages, classes, methods, and so on, which are different (the "diff" part) when two Java APIs are compared. Great for reporting what has changed between two releases of your product.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.
