Aeries Technology Java Developer Interview: Rounds, Questions and Preparation

What the job involves

A Java Developer at an Indian IT services company builds and maintains server-side applications, REST APIs, and database-driven systems for client projects. Freshers typically join as trainees or junior developers, working on coding, bug fixes, unit testing, and small feature modules under senior guidance. Day-to-day work involves Java, Spring Boot, SQL, and version control tools like Git, often in an Agile delivery team.

Role and Technical Knowledge

1. 1

   What is the difference between an abstract class and an interface in Java, and when would you use each in a services project?

   Cover that abstract classes allow shared code and state, while interfaces define contracts for multiple inheritance. Mention using interfaces for service APIs and abstract classes for common base logic.

2. 2

   Explain how you would design a simple REST API for a student record system using Spring Boot.

   Mention controller, service, and repository layers, HTTP methods like GET and POST, JSON request and response, and basic validation. Show awareness of clean separation of concerns.

3. 3

   What is the difference between HashMap and Hashtable, and how does HashMap handle collisions?

   Explain synchronization difference, null key and value handling, and that HashMap uses chaining or tree bins when collisions occur. Mention that Hashtable is legacy and slower.

4. 4

   How does JDBC work, and where does Hibernate or JPA fit in a typical Java project?

   Describe JDBC steps: load driver, get connection, create statement, execute query, process result, close resources. Explain that ORM tools reduce boilerplate and map objects to tables.

Practical Scenarios and Problem Solving

1. 5

   You are asked to fix a bug where an API returns a 500 error only for some users. How would you debug it?

   Talk about checking logs, reproducing with the same input, reviewing recent changes, and isolating whether it is a data issue, null pointer, or database constraint. Mention adding temporary logging if needed.

2. 6

   A client wants a new field added to an existing form and database table. What steps would you take from code change to deployment?

   Cover updating the entity or model, database migration script, API request and response, front-end change if needed, unit tests, code review, and deployment through the release process.

3. 7

   How would you write a SQL query to find the second highest salary from an employee table?

   Show a subquery with MAX and less than, or use LIMIT with OFFSET, or a window function like DENSE_RANK. Explain which approach works across different databases.

4. 8

   You need to write a unit test for a service method that calculates a discount. What would you test and how?

   Mention positive cases, boundary values, and invalid inputs. Use JUnit with assertions and mock dependencies if the method calls a repository or external service.

Project and Academic Background

1. 9

   Walk me through your final-year project. What was your role and which part did you code yourself?

   Be specific about your contribution, the technology stack, and one challenge you solved. Avoid claiming work you did not do, as follow-up questions will probe details.

2. 10

   In your project, how did you connect the Java backend to the database, and what issues did you face?

   Describe using JDBC or an ORM, connection configuration, and a real issue like connection leaks, slow queries, or data type mismatches. Explain how you fixed it.

3. 11

   Which data structure did you use in your project and why?

   Give a concrete example, such as using a HashMap for lookups or a List for ordered records. Explain the trade-off in terms of time or memory.

4. 12

   How did you test your project before submitting it?

   Mention manual testing, edge cases, and any unit tests you wrote. If you used JUnit or Postman, describe what you checked and what bugs you found.

Behavioural and HR Questions

1. 13

   Why do you want to join a services company like ours rather than a product company?

   Show awareness that services work involves multiple clients, learning new domains quickly, and teamwork. Mention exposure to different technologies and client-facing delivery.

2. 14

   Are you willing to relocate to a different city or work in a client location, possibly on a different technology stack?

   Answer honestly but positively. Services companies value flexibility, so express willingness to learn and adapt, while being clear about any genuine constraints.

3. 15

   Tell me about a time you worked in a team and had a disagreement. How did you handle it?

   Use a simple STAR structure: situation, task, action, result. Focus on listening, discussing with data or logic, and reaching a solution without ego.

4. 16

   Where do you see yourself in two years, and how do you plan to keep learning Java and related technologies?

   Show a realistic path from trainee to independent developer, mentioning certifications, side projects, or learning Spring Cloud, microservices, or cloud basics. Avoid vague answers like becoming a manager soon.