Dogma Systems interview questions

Firstly i applied through hirect from there my cv got selected and i receive one assignment. I need to complete that assignment within limited period of time. I completed the assignment then i got call for interview.

Applied Online, Remote Interview 2 Rounds- HR and Tech HR round: Intro, Some HR questions and basic java quetions based on OOPs, Strings, Collections etc. Knowledge of frameworks.. Tech Round: Java in depth, asked tricky internal working based questions.. Strings immutability and memory allocation.. Multithreading.. Few Questions on Hiibernate, Spring frameworks etc..