Deutsche Telekom Interview Question

What is functional programming, functional interface in java 8 print the square of each even number input.stream(p1 ->).filter(num % 2 == 0).forEach(System.print.out()) What are terminal and non terminal operators What kind are the ways of using multithreading in java What are different kinds of threadpool How are the client API routed to different services What kind of LB supports this How did one service know the endpoint of another service How did the properties file get filled for each service, on stage, dev, and prod