From the website itself:

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.

This repository contains my solutions to the problems I've solved or I'm working on.

I like the language and I use it, so that I don't get out of practice in java programming.