Tanla Platforms India Java Developer Interview: Rounds, Questions and Preparation

What the job involves

Java Developers in Indian IT services build and maintain backend components, REST APIs, and database-driven modules for enterprise clients. They work in Agile teams, fix bugs, write unit tests, and support deployments under tight deadlines. Freshers often start on maintenance or enhancement projects before moving to greenfield development.

Role and Technical Knowledge

1. 1

   Explain the difference between HashMap and Hashtable in Java. When would you use each in a backend service?

   Cover thread safety, null keys and values, performance, and legacy code. Mention that modern code prefers ConcurrentHashMap over Hashtable.

2. 2

   How does Spring Boot help you build a REST API faster than plain Java servlets?

   Talk about auto-configuration, embedded server, starter dependencies, and annotation-based controllers. Give a simple example of a GET endpoint.

3. 3

   What is the difference between checked and unchecked exceptions? How do you handle them in a service layer?

   Define each, give examples like IOException versus NullPointerException, and explain try-catch, custom exceptions, and global exception handlers.

4. 4

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

   Show a subquery or window function. Mention edge cases like ties and nulls, and how you would test the query.

Practical Scenarios

1. 5

   Your Java service is throwing a NullPointerException in production but not in your local environment. How do you debug it?

   Describe checking logs, reproducing with similar data, using a debugger or adding null checks, and reviewing recent code changes. Mention stack trace analysis.

2. 6

   A client reports that an API is slow during peak hours. What steps would you take to improve performance?

   Cover profiling, database indexing, connection pooling, caching, and reducing payload size. Mention measuring before optimizing.

3. 7

   You need to add a new field to an existing database table without breaking the running application. How do you plan the change?

   Talk about backward-compatible migrations, adding nullable columns, phased deployments, and testing with a copy of production data.

4. 8

   How would you write a unit test for a method that calculates an employee's bonus based on performance rating and salary?

   Mention JUnit, test cases for boundaries and exceptions, mocking dependencies, and keeping tests independent and fast.

Behavioural and Teamwork

1. 9

   Tell me about a time you had to learn a new technology quickly for a college project or internship.

   Use STAR format. Focus on the steps you took, the resources you used, and the outcome. Show willingness to learn.

2. 10

   Describe a situation where you disagreed with a teammate on a technical approach. How did you handle it?

   Show respect, data-driven discussion, and willingness to compromise. End with a positive result for the project.

3. 11

   How do you handle working on multiple tasks with tight deadlines, as often happens in IT services projects?

   Mention prioritization, communication with leads, time management, and asking for help when needed. Give a concrete example.

4. 12

   Give an example of a bug you introduced and how you fixed it. What did you learn?

   Be honest, explain the debugging process, and highlight the lesson learned, such as writing better tests or code reviews.

HR and Company Fit

1. 13

   Why do you want to join the IT services sector, and what do you know about companies like Tanla Platforms India?

   Research the company's domain, such as CPaaS or messaging. Connect your interest to learning opportunities and the service model.

2. 14

   Are you comfortable with relocation, rotational shifts, or working on legacy technologies if the project demands it?

   Answer honestly but show flexibility. Mention that you understand client requirements and are open to learning any technology.

3. 15

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

   Show ambition to grow technically and take ownership. Mention becoming a reliable team member, learning new frameworks, and contributing to design.

4. 16

   What are your salary expectations for this fresher role?

   Research typical fresher salaries in Indian IT services. Give a range or say you are open to the company's standard package for the role.