VRaptor3 is a fully-fledged Java Web framework focused on fast development and maintainable code. It intends to make RESTful application development easy. A resource corresponds to a business logic annotated with its path and HTTP method. It runs inside DI Containers (Spring or Pico out of the box) and, therefore, enables full integration with them. Also, using Hibernate is easier: its session is automatically injected by VRaptor, so you just have to use it. VRaptor3 is refactor-friendly, especially in its redirecting configuration. It is also nicely extensible.
mysql-diff is a commandline database structure comparator. It compares the structure of two databases. It currently works with MySQL. A database can be specified as an SQL script or as an URL to a running database. So the tool can compare two scripts, two live databases, or a database and a script. The tool outputs SQL DDL script that can be used to convert one schema to another.
The Google Singleton Detector, or GSD, is a tool which analyzes Java bytecode and detects the use of Singletons. It's not quite as simple as that, however. First, GSD doesn't only detect singletons; it detects four different types of global state, including singletons, hingletons, mingletons, and fingletons. Second, it outputs a graph with all these different types of static state highlighted, and shows all the classes that are directly dependent on them. The point of this tool is to allow you to see all of the uses of global state inside a project, as well as how they are all interrelated.
Autodia is a command line Perl application that generates UML class diagrams from source code, SQL, and database connections. It supports multiple programming languages including SQL, and can output images (using GraphViz/VCG/SpringGraph), Dia XML and Umbrello XML, or custom formats using templates.