1.What do you think is the best back end framework for Java? (because I am skillful only in Java for the moment)
2.Would it be better to learn Python and start writing my backend services with it?

Node.js

2. Yes

Would you please argument your answer :)

@architect With python you will need much less code and you will be able to write it quicker.

2. No, you have the option to choose go.

Spring. Spring Boot with MVC can get you a working server in under 5 mins.

I have tried Spring and I liked it a couple of months ago, but most people online recommend Node.js or Python :/

@architect spring and Java is still used plenty. It may not have the "cult following" of python and node, but many companies, especially larger ones, use it 100%.

What do you mean by 'backend java framework'? Are you looking for a java framework in which to do web development? You could check out www.playframework.com or grails.org

Well basicaly I am looking for backend framework (having in mind that I come from Java background)

What do you need the framework to do? What're you building?

Well I am not building anything in particular, but I want to find a job in the industry

Oh, well in that case learn about how the Spring IoC container/proxying works, both internally and how you put it all together. Spring jdbc and hibernate for database communication. It's always good to know when it's best to use an orm tool over straight sql too. Also, I'd get familiar with RESTful services and jaxrs