ArgoUML is the leading open source UML modeling tool and includes support for all standard UML 1.4 diagrams. It runs on any Java platform and is available in ten languages.
SQuirreL SQL Client is a graphical Java program that will allow you to view the structure of a JDBC compliant database, browse the data in tables, issue SQL commands etc, see Introduction. The minimum version of Java supported is 1.5.x as of SQuirreL vers
Or, Making Java Practical for Command Line Utilities
CruiseControl.rb is a continuous integration tool.