O2 (Czech Republic) Senior Java Developer interview questions

There was only one round. Firstly project manager told me that nice part of implementation is done and I'll be mostly fixing bugs! He also asked me what part of application should I work on and I answered front end. Then senior developer asked me virtual scenarios mostly on backend. DB, transactions etc. One question was front-end (spring MVC). Except some backend questions in virtual scenarios I answered all. Questions were little bit chaotic but I made right all straight questions to Portlets, SOAP, REST, Maven, Git, Branches, tags, news in Java 8, Open session in view etc. In the middle of interview HR and manager left the meeting room and I was continuing with Senior developer. At the end he asked me if I'm interested in software design because I have a lot of experience. In 2 days HR called me that they can offer only Junior salary. I did not accepted it.