..png)
Full Stack Java Interview Questions & Answers for Freshers (2025 Edition):
The world runs on Java from enterprise apps to Android, from banking systems to cloud-native microservices. But today’s recruiters no longer want “just Java programmers.” They want Full Stack Java Developers engineers who can handle the frontend, backend, database, APIs, and deployment.
If you’re a fresher preparing for interviews, this blog is your one-stop prep guide. We’ll cover:
Top Full Stack Java interview questions and answers (with explanations)
Real-world scenarios that recruiters use to test your logic
Tips to impress during HR and technical rounds
FAQs about careers, salaries, and interview strategy
Modern Java developers are expected to:
Know Core Java (OOPs, Collections, Exceptions, Threads)
Understand Spring Boot & REST APIs
Be familiar with JPA/Hibernate for ORM
Know basic frontend (HTML, CSS, JavaScript, React or Angular basics)
Handle databases (MySQL, PostgreSQL, MongoDB)
Understand Git, Maven, Jenkins, Docker basics
Let’s explore questions in each of these areas step-by-step.
Answer:
Object-Oriented
Platform Independent (runs on JVM)
Robust and Secure
Multithreaded and Portable
High Performance with JIT Compiler
Example:
Java’s “Write Once, Run Anywhere” capability allows your code to run on any device with a JVM.
|
Component |
Description |
|
JVM |
Executes Java bytecode |
|
JRE |
JVM + essential libraries |
|
JDK |
JRE + development tools (javac, jar, etc.) |
Encapsulation: Binding data & methods (e.g., getters/setters).
Inheritance: Reusing parent class code.
Polymorphism: Multiple forms (method overloading/overriding).
Abstraction: Hiding implementation details.
Example:
A Vehicle superclass with subclasses Car and Bike shows inheritance and polymorphism.
== compares memory addresses (reference).
.equals() compares content (values).
Example:
String a = new String("NareshIT");
String b = new String("NareshIT");
System.out.println(a == b); // false
System.out.println(a.equals(b)); // true
A constructor initializes an object when it’s created. It has the same name as the class.
Example:
class Student {
Student() { System.out.println("Student object created"); }
}
|
Feature |
Overloading |
Overriding |
|
Definition |
Same method name, different parameters |
Same method name, same parameters |
|
Compile/Runtime |
Compile-time |
Runtime |
|
Example |
add(int a, int b) & add(double a, double b) |
display() overridden in subclass |
public: Accessible everywhere
protected: Within package + subclasses
default: Within package only
private: Within same class only
|
Feature |
ArrayList |
LinkedList |
|
Storage |
Dynamic array |
Doubly linked nodes |
|
Access speed |
Fast random access |
Slower random access |
|
Insertion/deletion |
Slower (resizing) |
Faster (pointer change) |
Used for exception handling.
Example:
try {
int result = 10/0;
} catch(ArithmeticException e) {
System.out.println("Cannot divide by zero!");
} finally {
System.out.println("End of program");
}
Answer: Executing multiple threads concurrently to improve performance.
Example: Background data loading while UI runs smoothly.
A framework that simplifies Spring development by providing auto-configuration, embedded servers, and production-ready features.
Auto Configuration
Embedded Tomcat/Jetty
Easy to create REST APIs
Ready for Microservices
Simplified Dependency Management
Answer: REST (Representational State Transfer) is an architectural style for web services.
Example:
GET /students → fetch list
POST /students → create record
PUT /students/{id} → update
DELETE /students/{id} → delete
Annotation in Spring Boot that combines @Controller and @ResponseBody.
It marks a class as a REST API controller.
Used for dependency injection.
Example:
@Service
class StudentService { }
@RestController
class StudentController {
@Autowired
StudentService service;
}
To configure values like port, database credentials, and other environment variables.
Use properties like:
spring.datasource.url=jdbc:mysql://localhost:3306/studentdb
spring.datasource.username=root
spring.datasource.password=root
JPA (Java Persistence API) - specification for ORM.
Hibernate - implementation of JPA.
It maps Java objects to database tables.
Marks a class as a table in the database.
@Entity
class Student {
@Id int id;
String name;
}
Using @ControllerAdvice and @ExceptionHandler.
Example:
@ControllerAdvice
public class GlobalExceptionHandler {
@ExceptionHandler(Exception.class)
public ResponseEntity<String> handleException(Exception e) {
return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(e.getMessage());
}
}
HTML: Structure of the webpage
CSS: Styling and layout
JavaScript: Interactivity and logic
Document Object Model - structure of the HTML page that JavaScript can manipulate.
|
Keyword |
Scope |
Reassignable |
|
var |
Function |
Yes |
|
let |
Block |
Yes |
|
const |
Block |
No |
AJAX (Asynchronous JavaScript and XML) allows web pages to communicate with servers without reloading.
Frontend frameworks for building dynamic, single-page applications (SPAs).
A unique identifier for records in a table.
Process of reducing redundancy and ensuring data integrity in database tables.
SELECT * FROM students WHERE marks > 60;
INNER JOIN: Returns only matching rows.
LEFT JOIN: Returns all rows from left table and matching rows from right.
Index improves query speed by maintaining a smaller lookup structure.
Example:
CREATE INDEX idx_name ON students(name);
Build automation tool used to manage dependencies and project structure.
Version control system for managing source code and collaboration.
CI/CD automation - builds, tests, and deploys applications automatically.
Containerization platform that packages application with dependencies to run anywhere.
An architectural style dividing applications into independent, loosely-coupled services communicating via APIs.
Sample Answer:
“I love solving problems end-to-end - from database to UI. Java gives me backend power, and learning frontend helps me visualize what users experience. I enjoy working on complete solutions, not just one layer.”
“I’m consistent and curious. I don’t just code; I understand why a feature matters to users.”
“I check logs, reproduce the issue locally, analyze stack trace, and use tools like Postman or debugger to trace flow.”
“By reading documentation, following communities, watching YouTube tutorials, and practicing on GitHub.”
“It’s like a waiter who takes your order (request) and brings you food (response) from the kitchen (server).”
Reusable solution for common design problems (Singleton, Factory, MVC).
A design pattern where objects are provided dependencies externally rather than creating them inside.
|
Type |
Monolithic |
Microservices |
|
Structure |
Single large codebase |
Independent services |
|
Deployment |
Entire app redeployed |
Each service independently |
|
Scalability |
Harder |
Easier |
JSON Web Token - used for authentication between client and server.
Cross-Origin Resource Sharing allows or restricts web resources from different domains.
Use Spring Security, token-based auth, HTTPS, and validation checks.
Maintaining multiple versions (v1, v2) of APIs to avoid breaking old clients.
Use libraries like Jackson or Gson for parsing and serialization.
Introduced in Java 8 - allows concise function expressions.
Example:
List<Integer> list = Arrays.asList(1,2,3);
list.forEach(n -> System.out.println(n));
Java 8 feature to process collections efficiently using filter, map, reduce.
Practice coding daily — focus on logic, not memorization
Build a mini-project — a CRUD app using Spring Boot + React/Angular + MySQL
Understand fundamentals deeply — OOPs, REST, Collections
Mock interviews — practice speaking confidently
Prepare HR answers — “Tell me about yourself,” “Why Java?”
Know your resume project — be ready to explain architecture and tools
“Explain any project you worked on using Full Stack Java.”
Sample Answer:
“I developed a Student Management System using Spring Boot (backend), React (frontend), and MySQL (database).
Frontend built with React fetches data via REST API.
Backend uses Spring Boot + JPA for CRUD operations.
Authentication handled using JWT.
Deployed via Docker on AWS EC2.
It helped me understand the entire development lifecycle from coding to deployment.”
₹4.5 – ₹6.8 LPA (Hyderabad, Bangalore, Pune). With projects and internships, ₹7 – ₹10 LPA possible.
Yes! Anyone with logical thinking can learn. Institutes like NareshIT offer structured bootcamps that start from Java basics and build step-by-step to deployment.
Projects (GitHub link)
Technologies (Java, Spring Boot, React/Angular, MySQL)
Internship or mini-project
Achievements (certifications, hackathons)
Product startups
IT service companies
Digital agencies
FinTech, HealthTech, and EdTech firms
Study concepts from this Q&A.
Practice small CRUD projects.
Revise key topics daily.
Take mock interviews.
Watch placement videos from NareshIT alumni for real patterns.
Focus on Java 21 (latest LTS) - it introduces better performance, pattern matching, virtual threads.
Yes. HTML, CSS, and JavaScript basics are mandatory. React or Angular adds extra edge.
Spring Boot, Hibernate, MySQL, Maven, Git, Docker, Jenkins, Postman.
Student Management System
Online Job Portal
Task Tracker App
E-Commerce Cart
Blogging Platform
Extremely bright Java remains enterprise-standard, and companies prefer developers who can handle both frontend and backend. With GenAI and Cloud integrations, demand is only rising.
Cracking a Full Stack Java interview isn’t about memorizing answers it’s about understanding concepts and showcasing confidence.
You’ve now gone through 50+ real interview questions, HR scenarios, and FAQs that prepare you for any interviewer’s curveball.
Now, it’s your turn:
Practice.
Build projects.
Revise daily.
Stay confident.
At Naresh IT, our Full Stack Java course is placement-oriented, taught by real-time industry experts, and designed to make you interview-ready with hands-on projects and mock interviews.
Call to Action:
Join Naresh IT’s Full Stack Java Program Today!
Hyderabad | Online | Offline
100% Job Assistance • Real-Time Trainers • Placement Drives
www.nareshit.com
+91 8179191999 
+91
8179191999
.jpg)
.jpg)
_Method.png)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.png)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
..jpg)
..jpg)
_Skills_&_Jobs.png)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
..png)
.jpg)
_8_Weeks_to_Career_Success.png)
..png)
.jpg)
.jpg)
.jpg)
.png)
.png)
.png)
_Skills,_Syllabus,_and_Career_Roadmap.png)
.png)
.png)
_Implementation_in_Playwright_A_Complete_Non-Coding_Guide_(1).png)
..png)
.png)
.png)
..png)
.png)
.png)
.png)
_NARESH_IT.png)
.png)
.png)
