Adyen Software Engineer Java Developer interview questions

I applied as a java developer (graduate program). There were 5-6 rounds which consumed a lot of time (If you pass one round, then you'll be moved forward). HR screen > introductory session with one senior dev (introduce yourself, why you're interested in Adyen) > Hackkerank > Code review with one tech lead and one senior > so on.. I failed at code review, they asked a lot of deep question to determine whether you really understand java.