Java Developer interview prep

What the job involves

A Java Developer in Indian IT services builds and maintains enterprise applications using Java, Spring, and SQL for clients across domains like banking, retail, and insurance. Freshers typically join as graduate engineers, undergo 4-12 weeks of training, and then work on coding, bug fixes, unit testing, and production support under a tech lead. The role demands strong fundamentals, willingness to learn frameworks, and comfort with client-facing delivery timelines.

Role and Technical Knowledge

1. 1

   Explain the difference between JDK, JRE, and JVM.

   A strong answer defines each: JVM runs bytecode, JRE includes JVM plus libraries, JDK includes JRE plus development tools. Mention that Java is platform-independent because of the JVM.

2. 2

   What is the difference between an abstract class and an interface in Java?

   Cover that abstract classes can have constructors and state, while interfaces support multiple inheritance and default methods since Java 8. Give a small example of when to use each.

3. 3

   How does Spring Boot simplify Java web development?

   Mention auto-configuration, embedded servers like Tomcat, starter dependencies, and reduced XML. Relate it to building REST APIs quickly in a services project.

4. 4

   Write a SQL query to find the second highest salary from an Employee table.

   Show a subquery or LIMIT/OFFSET approach. Explain that you would test edge cases like duplicate salaries and nulls.

Practical Scenarios

1. 5

   You are asked to fix a bug in a Java application that works fine in testing but fails in production. How do you approach it?

   Talk about checking logs, reproducing the issue, comparing environments, and using debugging tools. Mention communicating with the QA and support teams before making changes.

2. 6

   A client wants a new REST endpoint to fetch customer details by ID. How would you design it?

   Describe the URL structure, HTTP method, request/response JSON, status codes, and validation. Mention using Spring Boot with a service and repository layer.

3. 7

   Your code passes unit tests but fails code review because of poor exception handling. What do you do?

   Accept feedback, explain how you would add specific catch blocks, log errors properly, and avoid swallowing exceptions. Show willingness to learn team standards.

4. 8

   You need to connect a Java application to a MySQL database. What steps do you follow?

   Cover adding the JDBC driver, creating a connection, using PreparedStatement to avoid SQL injection, and closing resources. Mention connection pooling for production.

Project and Internship Discussion

1. 9

   Explain your final-year project and your specific contribution.

   Summarize the problem, tech stack, your role, and one challenge you solved. Keep it under two minutes and avoid claiming work you did not do.

2. 10

   Which Java concepts did you use in your project and why?

   Name real examples like collections for data storage, inheritance for code reuse, or JDBC for database access. Explain the trade-off you considered.

3. 11

   If you had to add a new feature to your project now, what would it be and how would you implement it?

   Pick a realistic feature, outline the design, the classes or APIs needed, and how you would test it. Show structured thinking rather than perfect code.

Behavioural and HR Questions

1. 12

   Are you comfortable working in rotational shifts or relocating to a different city for a project?

   Answer honestly and positively if you are flexible. Mention that you understand Indian IT services often require shift and location flexibility for client projects.

2. 13

   Tell me about a time you worked in a team to meet a deadline.

   Use a simple STAR structure: situation, task, action, result. Focus on your specific contribution and what you learned about collaboration.

3. 14

   Why do you want to join a services company like ours instead of a product company?

   Highlight exposure to multiple domains, client-facing work, structured training, and long-term learning. Avoid saying it is only for job security.

4. 15

   Where do you see yourself in three years as a Java Developer?

   Show a realistic path: strong coder, then module lead or specialist in a framework like Spring or cloud. Mention continuous certification and upskilling.