Why do we need Maven or Ant, if we already have Eclipse?
I think this question is an extension of http://stackoverflow.com/questions/7884809/compare-to-the-ide-for-java-do-we-still-need-ant

There are answers for the question above, but I wish to know an concrete example of using Maven or Ant. 

When I develop in Eclipse, Eclipse does everything for me and I just need to click run button. And also, Eclipse can let you export your code to an runnable jar or even .exe for windows.

So I really don't know why I need Maven or Ant.

And also if I do need, **which one should I choose, Maven or Ant?**
Why do we need Maven or Ant, if we already have Eclipse?
===

I think this question is an extension of http://stackoverflow.com/questions/7884809/compare-to-the-ide-for-java-do-we-still-need-ant

There are answers for the question above, but I wish to know an concrete example of using Maven or Ant. 

When I develop in Eclipse, Eclipse does everything for me and I just need to click run button. And also, Eclipse can let you export your code to an runnable jar or even .exe for windows.

So I really don't know why I need Maven or Ant.

And also if I do need, **which one should I choose, Maven or Ant?**