Java Engineer Interview Questions and Answers

Designing architecture for a messaging app like Whatsapp

• Use a client-server architecture with a central server handling message routing and storage

• Implement end-to-end encryption for secure communication

• Utilize push notifications for real-time message delivery

• Scale the system horizontally to handle large user base

• Consider implementing features like group chats, voice/video calls, and file sharing

Optimal solution for sorting an array of strings using built-in sorting algorithm in Java.

• Use Arrays.sort() method to sort the array of strings in Java.

• Ensure to import the Arrays class before using the sort() method.

• Example: String[] arr = {"banana", "apple", "orange"}; Arrays.sort(arr);

Create a Spring Boot service to retrieve data

• Create a REST controller to handle incoming requests

• Use Spring Data JPA to interact with the database

• Implement service layer to handle business logic

• Use ResponseEntity to return data with appropriate HTTP status codes