Core Java and Java 8 What is the difference between ArrayList and LinkedList? When would you use one over the other? Explain the concept of functional interfaces in Java 8. Can you name a few built-in functional interfaces? How does the Stream API work in Java 8? Write a code snippet to filter a list of integers and find the sum of even numbers. Collection Framework How does a HashMap work internally? What happens if two keys have the same hash code? What is the difference between HashSet and TreeSet? How does TreeSet maintain order? Spring Boot What is dependency injection in Spring Boot? How does it help in building loosely coupled applications? How do you handle exceptions globally in a Spring Boot application? Explain the use of @ControllerAdvice. Microservices What are the key differences between monolithic and microservices architecture? What challenges do microservices solve? How do microservices communicate with each other? Explain the use of REST APIs and messaging queues. Design Patterns Explain the Singleton design pattern. How can you implement a thread-safe Singleton in Java?
