Devexperts Software Trainee interview questions

First I applied for internship, because one of employers in Devexperts is a lector in our University. It was in the very beginning of December. After about one week one of HR's invited me for the interview. I was asked to solve two quizes. First is about Java and second one is about some Maths and other useful skills in programming. After that tests interviewer came in and I had 5 hours of interview. There were a lot of questions about Java, algorithms, data structures, OOP principles, design patterns and so on. And after 3 months in March I was invited for the second interview with my future team members. And I started my work in April.