L-1: Top10Employees list using Java 8 streams. Salary 50000/- using Java 8 streams Salary 50000/- and age

Question

L-1: 
Top10Employees list using Java 8 streams.

Salary >  50000/- using Java 8 streams

Salary >  50000/- and age < 40 (DOB)  using Java 8 streams

{1,2,3,4,5} sum = 6 
Output {1,5} {2,4} using loops

Questions: 
Java8 streams 
Functional interfaces 
HashMap internally working 
Red black tree

@SpringBoot Application 
What happens without giving to the query params in @put method
Schedulers 
CB pattern 
Uses of Kafka

L-2:
Spring boot & Microservices architect 
How to communicate Micro services 
How to call external APIs

Deloitte