It was a hell of a ride, I applied through employee referal, and got answer after 1-2 days.
The whole process took about 2 weeks, but just because I did not have time to attend interviews during the first week.
I have marked the interview easy, as for me it was easy, it required a broad knowledge of a lot of things, and deep knowledge in a few, some parts was a weakness for me, but the interviewers was easy on those, and recognized that I have an overview about the area, but does not have the deep experience or knowledge on those parts.
First interview was a recruiter screening, simple walkthrough over my resume, project I worked on, why I would like to apply and such.
The interesting part was that it was the first hiring round for a second shift in the Budapest office, and I would have to explain why I would like to apply for this position as this is clearly not ideal to my social life if I work until 11 pm every weekday. However, as I am pretty much a late night person, I really prefer to be able to stood up even until 3 or 4 am and if I don't need to bother getting up until noon that is the perfect one for me :) Of course as I am not native english, there were a small english communication skills check as well, however the rest of the interviews went in english except one with one of the local managers.
The next round was with the regional manager via telco, it was mostly about personality, and resume things, but at the end we got to customer handling scenarios, where I needed to proof that I am able to communicate even hard things or in harsh escalated situations as well.
Third round was with one of the local managers, who is a technical guy pretty much, started as a CEO as well, who was similarly to me coming from the Java development field. It was the one and best interview of mine ever so far. We discussed about system administration related things, linux shell commands shell scripting and such, which was not my strongest, but it was not about the hard hands on knowledge but the perspective I am seeing the problems. The best part was that when I told him I have never done that before, but if I get to google I can find the solution I am sure, so he gave over his laptop with a clear browser, and said: then find it out, and show me how you do it. I was able to do it :)
After these parts, we talked about the projects and problems I have faced, the main aim was to find out how I approach a problem, what things I try to check, what I am asking for, and how I find a solution for the problem. It went well, and at the end I re-solved an already solved case from scratch.
The fourth round was a purely technical interview via telco with one of the COEs located in London, we deep dived into Java internals (Java Frameworks, concepts, memory management, GC, references, threads, locking, everything) as that was my strongest skill, then we touched on shell scripting and file system internals, processor and hardware specific stuff, networking, and database concepts (that was my weakest, as the last database related project of mine was 8 years before the interview).
As I felt the main aim is to see what I know, and what I don't know, if I said that I don't know this part, then we skipped.
After this I was in and accepted, and we agreed that I will get my offer next year, as the last interview round was on the 23rd of December.