Ant (Score 1)

It is my firm belief that Ant is still the most powerful and flexible Java development tool available. A single XML file can be distributed among developers (regardless of platform), integrated into an IDE or used along side a simple text editor, then used with little or not effort. Ant can be extended with "plugins" or tasks... making it integrate with version control systems, documentation-creation tools (e.g. doxygen), etc.

There's a reason other popular IDEs like Eclipse and JBuilder include support for Ant build.xml files!