Most fresher interviews for Java full stack roles follow the same pattern. The interviewer checks Core Java first, then asks how you built something with Spring Boot and a database. Memorised answers rarely survive the follow-up question. A small project you can explain does.
Below are the questions that come up most often, grouped by topic, with what to practise for each.
Core Java
1. What is the difference between an interface and an abstract class? Practise: write one interface and two classes that implement it, then explain why you did not use inheritance.
2. How does a HashMap store and find a value? Practise: put ten entries into a HashMap, print them, and explain why the order is not guaranteed.
3. What is the difference between checked and unchecked exceptions? Practise: handle a file-not-found case properly instead of catching every exception.
4. Why are Strings immutable? Practise: compare building a long string with + against StringBuilder.
Spring Boot and REST APIs
5. What does @RestController do? Practise: build one controller with GET and POST endpoints for a single resource.
6. How do you validate a request? Practise: add validation rules to the request class and check that a missing field returns 400, not 500.
7. What is dependency injection, in plain words? Practise: explain how your controller gets its service without creating it.
Database: MySQL and Hibernate
8. What is the difference between an INNER JOIN and a LEFT JOIN? Practise: write both on two small tables and compare the row counts.
9. What does Hibernate do for you? Practise: save and read one entity, then look at the SQL it generates.
10. What is the N+1 query problem? Practise: load a list with related records and count the queries in the log.
About your project
11. Walk me through your project. Practise: a two-minute explanation: what it does, one design choice, one bug you fixed, and one thing you would improve.
12. How did you test it? Practise: list the valid and invalid requests you tried and the response code for each.
How to prepare in the last two weeks
- Rebuild your project from scratch once, without copying.
- Answer each question above out loud, in under one minute.
- Keep the code in a public repository with a short README.
Frequently asked questions
Do freshers need Spring Boot for Java full stack interviews?
Most full stack roles ask about it after Core Java, so one small Spring Boot project helps.
How many projects should a fresher show?
One finished project you can explain well is more useful than several unfinished ones.
Learn it with practice
ScholarLogic’s 5-month Java Full Stack training in Bangalore covers Core Java, Spring Boot, Hibernate, MySQL and REST APIs, in classroom batches at BTM Layout, Bengaluru, and in live online batches. You can book a free demo class from the course page. For fees, batch dates and placement support terms, please contact a ScholarLogic counsellor on +91 78923 93639.
Related: Interested in machine learning and statistics as well? See our data science course in Bangalore.
