Pregunta de entrevista de Barclays

Phone interview questions: 1) Difference between sprint backlog vs product backlog ? 2) Define ways to implement multi-threading. 3) Define abstract class. Why is it used ? Face to face interview questions: 1) Describe singleton class. How would you implement it in multi-threaded scenario. 2) Every interviewer had somehow read the same article where it is focused on creating singleton the best way for multi-threaded environment and everyone who came in asked the same question again and again. 3) How would you load a large data using web via http? Other questions were pretty standard java questions.