All company interviews
Example Technology Company

Java Backend Developer Interview Questions

Interview experience for a candidate with 8 years of experience.

Interview DateJuly 2026
Candidate Experience8 years
Tech StackJava, Spring Boot, REST API, PostgreSQL

Interview Questions

Core Java 9 questions
  1. What is the Singleton Design Pattern?
  2. How do you create a Singleton class in Java? What are the different ways to implement it?
  3. What is an immutable class? How do you create one in Java?
  4. What is the difference between a List and a Set?
  5. What is ConcurrentModificationException? Why does it occur, and how can you prevent it?
  6. What are the different types of thread pools available in Java's Executor Framework?
  7. Explain the lifecycle of a thread in Java.
  8. How does a HashMap work internally in Java?
  9. What is Garbage Collection in Java? How does it work?
Spring & Spring Boot 4 questions
  1. What is the difference between @Component and @Service in Spring?
  2. What is the difference between the Spring Framework and Spring Boot?
  3. How do you define a Many-to-Many relationship in Spring Boot using JPA/Hibernate?
  4. Which design patterns have you used in your project?
Production Support 2 questions
  1. How do you analyze and troubleshoot production issues in a Spring Boot application?
  2. Describe your step-by-step approach to debugging a production issue.
SQL 1 questions
  1. Write an SQL query to find the employee with the second-highest salary.