What is build automation software (for example, Ant)?

Question

I see reference of ant a lot but I don\'t get exactly what its meant to do? from what i\'ve heard its supposed to compile your projects but can\'t i just do that by clicking Run

Answer 1

Eclipse is using ant for building, running, deploying, ...

"Ant is a Java-based build tool. In theory, it is kind of like Make, without Make's wrinkles and with the full portability of pure Java code." (from link text