Tata Consultancy Services Sr. Software Engineer interview questions

Toughest interview in a while Find a all bst in a binary search LRU CACHE DESIGN A EVENT BUS Design a twitter DESIGN A EVENT BUS Design a twitter Interviewer was polite and helped with the process. Help me solve this questions

1) Features of Java 8. 2) How we can avoid the duplication entry using list. 3) what is the difference between abstraction and interface 4) Concept Thread how it works. 5) what is the concept of method overloading and riding 6) What are the REST HTTP methods. 7) About your project and role you worked on. 8)How heap memory and stack memory works in jvm. 9) About Collection interface (Explin of all the interface)