This document summarizes a Mercurial extension called Diff+ that analyzes Java source code files. The extension gets two revisions of a project from the Mercurial repository and prints the difference in the number of classes and methods between the revisions. It uses the Mercurial API to access the repository and revision data. The extension is configured in the Mercurial extensions section and can be run with the "hg analyze-java" command. As an example, it showed running the extension between two revisions and outputting that there was a difference of 44 classes and 234 methods between the revisions.