WebBee Global interview questions

interview started with introduce yourself and you project. 1) then he said that as you have worked on rest api, so tell me is rest api single threaded or multithreaded by default. 2) then he asked me what were the changes introduced in java 8. 3) what are default methods? 4) is it necessary to override default methods? 5) why were default methods introduced?? and some other tricky java OOPs based questions were also asked