Multi-threading, Collections, Core Java, Spring & SQL

1st round interview questions: design pattern: builder design, factory design spring boot annotations: setter, constructors dependency injection, 3 ways to inject @configuration, @springbootapplication --?, @transaction annotation @service @controller @repository what's difference , and what actually it does with those annotations. Spring vs spring boot, why? left outer join, outer join, what happens for no row selected ORM vs JDBC JPA, JDBC template @entity @component scan, CompletableFuture, Executor framework for API calls? blocking calls? Thread.sleep when to use? notify , wait, producer consumer hashtable vs hashmap, fail fast and fail safe, concurrrenthashmap vs hashtable sorting algorithm: bubble sort streams for loop vs general for loop hashmap collision explain internal, whats tree inside hashmap? when size of hashmap grows? why tree is introduced in hashmap? how searching will be faster in it? initially, is it arays or arraylist in hashmap? internal working of hashtable when you last use thread or executor framework yield, join