Clover is a Java code coverage analysis tool. Key features include per-test code coverage, test optimization (aka selective testing), interactive and historical HTML reporting, IDE integration with Eclipse, IntelliJ IDEA, RAD, and NetBeans. It also works with Ant, Maven, and other command line tools.
Saros is a Eclipse plugin for collaborative text editing that in particular targets distributed pair programming (also called remote pair programming), but can support arbitrarily many participants at once. All members of a session have an identical copy of an Eclipse project and Saros keeps these copies in sync as editing progresses.
Chaplin ACT is a Java class transformer which brings several modern language concepts into Java: contexts, composites, roles, traits (mixins), runtime type conversion, dynamic method signatures, method and field aggregators, etc. Using these concepts makes designing loosely-coupled applications and writing cohesive code easier. Chaplin can work either as a JVM agent or as a post-compilation class transformer. It does not introduce any new syntax. All functionality is implemented by means of the standard Java language elements.
AntTask-GenerateXML is an Ant task that uses XMLBeans to create example XML instances from a W3C schema. It is especially useful for looking at pieces of schema, as you can set the element you wish to use as the root one. It will use the values from enumerations as the fixed/default values for attributes and elements if they are set. It obeys the XML type system with the exception of regex/patterns.