Someone can fucking explain why exists language like groovy?!?! It's the fucking same language of Java, only with few extra features! Why the hell I have to choose groovy over java?

Groovy is for scripting, you can just run a groovy script without intermediate compiling and explicitely run the bytecode.

But you're somehow right, nearly all java can be run as groovy scripts, so it's tempting to write java as groovy script instead of real groovy.

Groovy is nice for java developers, because it's easy to get something going, especially no syntactical bullshit to learn in first place.

@ddephor I understand that is a good scripting tool for java devs that wants to use java apis, but at the end there are a far good languages for that scope: python, javascript, ...

Javascript is not suitable for standalone scripts. Python is nice and you can do so much with it, but it has those terrible syntax flaws, binary data handling is awful and even filesystem access is not implemented consistent (some in os.*, others in shutil.*).

Groovy is just another script language with the benefit of integrating pure java if you want to. Groovy also has it's flaws, I don't like file access, it's just messy and non-intuitiv.

There are far worse script languages like perl, which I played with recently, after many years of forgetting it, and I wouldn't use perl nowadays unless forced to.

If you don't need groovy, then don't use it, but there are many use cases for it.