HCL Senior Java Developer interview questions

Tell about yourself, Project, Reason for changing jobs, Since this is my third company they asked why you left 1, 2 companies. They asked do you hold any offer in hand, and the technical interviewer asked the Current CTC, & Expected CTC, if holding offer those details too. How fair to ask salary discussion in the technical discussion?. Its really the mood of interviewer to be stay unbiased after knowing these information. My interviewer was kind enough to ask questions from basics to recent most technology. a) First round questions 1) Difference between interface vs abstract class 2) What are the ways to implement thread class 3) Define Thread Pooling 4) Say the collections used in your project 5) How you write Webservices 6) How you map the httpmethods to respective functions. 7) A program to rearrange the numbers in from 1,2,3,6,-1,10,5,-10,88 to -1, 1, 2,3,5,6,-10, 10,88 8) Jsp Implicit objects 9) Classification of Jstl tags. Round 2 : 1) How you invoke a rest web service from plain java class without using spring or Jax-Rs 2) How to improve the performance of a web service which was gradually increases the response time from 1 Second to 15 min.? 3) After a month, the webservice objects need to be cleared to keep the memory free. How will you achieve this? 4) How will you make 2 individual machine to speak with each other in internet? 5) Which collection will you use to keep the recent most five elements only?