Ant,Maven and Gradle

All these are build tools

Ant + ant-contrib is essentially a turing complete programming language that no one really wants to program in.

Maven tries to take the opposite approach of trying to be completely declarative and forcing you to write and compile a plugin if you need logic. It also imposes a project model that is completely inflexible. Gradle combines the best of all these tools:

• It follows convention-over-configuration (ala Maven) but only to the extent you want it
• It lets you write flexible custom tasks like in Ant
• It provides multi-module project support that is superior to both Ant and Maven
• It has a DSL that makes the 80% things easy and the 20% things possible (unlike other build tools that make the 80% easy, 10% possible and 10% effectively impossible).

Gradle is the most configurable and flexible build tool I have yet to use. It requires some investment up front to learn the DSL and concepts like configurations but if you need a no-nonsense and completely configurable JVM build tool it's hard to beat.