Spring Boot Interview QnA (2026)- Spring Boot 3.x Included

by devs5003 - May 13, 2026May 14, 20260

Spring Boot Interview QnA (2026) Spring Boot is now the default choice for building Java backend and microservices applications, so it appears in almost every Java interview. This article collects the most important Spring Boot interview questions with simple explanations, diagrams, and code examples so even beginners can follow along. Basics of Spring Boot: Spring Boot Interview QnA 1. What is Spring Boot? Short answer: Spring Boot is a framework built on top of the Spring Framework that makes it easy to create production‑ready, stand‑alone applications with minimal configuration. Simple explanation: Traditional Spring needs a lot of XML/Java configuration, manual server setup, and dependency management. Spring Boot gives you sensible defaults, auto‑configuration, and embedded servers (like Tomcat), so you can focus on writing business logic instead of infrastructure

Spring Boot Configuration Priority Order: CLI, Env Vars & Profiles

by devs5003 - May 11, 2026May 12, 20260

Spring Boot Configuration Priority Order If you have ever stared at your Spring Boot application wondering "Why is it picking the wrong port?" or "Where is this database URL coming from?" You are not alone. One of the most common sources of confusion among Java developers is how Spring Boot decides which configuration value to use when the same property is defined in multiple places. This guide breaks down the externalized configuration property priority into a simple, visual hierarchy that you can bookmark for your next project or technical interview. What Is Externalized Configuration in Spring Boot? As per Spring Boot official documentation on externalized configuration, Externalized configuration means keeping your application settings outside your compiled code so you can change behavior without rebuilding the JAR. Spring Boot supports multiple

What Interviewers Look for in Java Interviews: An Interviewer’s Score Card

by devs5003 - February 24, 2026April 1, 20260

What Interviewers Look for in Java Interviews: An Interviewer’s Score Card If you’ve ever walked out of a Java interview thinking, “I answered everything… so what went wrong?”, This article is for you. Most Java developers who fail interviews are not bad developers. They're actually quite good. They know their Collections. They've worked with Spring Boot. They've built microservices. Some of them have better code on GitHub than the person who interviewed them. And yet, they got rejected. Why? Because interviews don't just test what you know. They test how you communicate what you know. And most developers have never been told what the interviewer is actually writing while they speak. I've been on both sides of this table. As a candidate, I failed interviews I

The Ultimate Spring Boot Annotation Checker Tool (Cheat Sheet 2026)

by devs5003 - February 16, 2026February 21, 20260

Spring Boot Annotation Checker Tool Are you still guessing whether to use @Component, @Service, or @Bean? You are not alone. In 90% of Spring Boot interviews, candidates fail not because they can't code, but because they can't explain the intent behind the annotations they use every day. "It just works" is not a senior-level answer. To help you master this, here a free interactive decision tool. Stop memorizing definitions and start understanding the why. 🛠️The Spring Boot Annotation Checker Tool Don't know which annotation fits your scenario? Answer the 2 simple questions below to get the exact answer. Here is the complete Spring Boot Annotation Checker tool. This is a comprehensive, interactive decision tree that covers the most confusing annotations for mid-level developers (Stereotypes, Injection, Web Layer, Configuration). Top 3 Annotation Confusions (Interview Favorites) The tool

Spring Boot Annotations MCQs

by devs5003 - May 7, 2025May 3, 20260

Spring Boot Annotations MCQs Understanding annotations in Spring Boot is essential for any Java developer working on enterprise-grade applications. These annotations simplify configuration, reduce boilerplate code, and help in building robust applications faster. Whether you're preparing for technical interviews, certification exams, or just aiming to solidify your Spring Boot foundation, mastering Spring Boot annotations is non-negotiable. Need to revise annotations first? Read "Spring Boot Annotations Guide." In this article, we will explore a set of Spring Boot Annotations MCQs that cover: Concept-based questions to test your theoretical knowledge Code-based questions to check your practical understanding Scenario-based questions to simulate real-world use cases Each question is carefully created with detailed explanations and covers both correct and incorrect options to help you learn and revise effectively. So,

Spring Boot Chat App with DeepSeek and Ollama

by devs5003 - February 13, 2025May 3, 20260

This tutorial provides a comprehensive guide to implement an intelligent chat application using Spring Boot, integrated with both DeepSeek and Ollama's local LLM capabilities. As these are locally installed tools, there are no chances of latency from internet roundtrips. We can process requests directly on our local server. Using it, we can train the AI our unique terminology such as company jargons, industry-specific knowledge, local dialects. Additionally, we can modify the model directly without relying on cloud provider updates. At the later stage, we can transition to cloud easily as the same Spring Boot code works both ways. This approach gives ultimate control while teaching foundational AI/software integration concepts used in enterprise systems. Let's go through a step-by-step article on Spring

DeepSeek Spring AI Integration Using Java Spring Boot

by devs5003 - February 6, 2025May 3, 20260

DeepSeek is a smart AI tool that helps computers understand and respond to human language. It behaves like a digital assistant that can answer questions, write text, or even generate code! Whether you want to build a chatbot, automate customer support, or create an app that "talks" to users, DeepSeek provides the brains to make it happen. It acts like a super-smart friend who is always ready to help with words, ideas, or solutions. Integrating DeepSeek (or any custom AI model) with a Spring AI project involves several steps. In this article we will go through a step-by-step tutorial on 'DeepSeek Spring AI Integration Using Java Spring Boot'. We will explore how to connect DeepSeek locally with a Spring AI project and test the

How to handle Exceptions in Spring Boot?

by shwetas8536 - January 24, 2025May 18, 20253

Every one of us spend ample amount of time in learning big topics of Spring & Spring Boot. For example, Spring Boot REST, Spring Boot MVC, Spring Boot Security and many more, but generally we don't think about 'How to handle Exceptions in Spring Boot?'. This topic might become the most important for running the application without any interference. Also, it is very helpful in making other developers understand our code flow easily. Even finding out the origin of errors & exceptions becomes very irritating, if we have not handled them properly in our code. Sometimes, we need to debug the whole flow of code to find it out & resolve accordingly. In this way, Exception handling plays an important role

How to implement JWT Authentication in Spring Boot Project?

by shwetas8536 - March 15, 2024May 3, 202612

No one can deny from the fact that Security is a vital feature of a production ready application. Although we can secure one web application using In-memory authentication, JDBC Authentication or via UserDetailsService. But when one application uses the services of other application internally, then implementation of security with webservices concept becomes important. In this situation we secure our application using a token which has a particular period of validity. In this article, we are going to learn 'How to implement JWT Authentication in Spring Boot Project?' to understand the concept behind JWT(JSON Web Token) Authentication as a whole. As JWT stands for 'JSON Web Token', it is clear that the token holds the data in the form of JSON only. Moreover,

Spring Boot 3 Migration- Migrate Spring Boot 2 To Spring Boot 3

by devs5003 - January 20, 2024November 18, 20253

After going through the major highlights of 'New Features in Spring Boot 3.0, it's time to check the process of Spring Boot 3 Migration ('How To Migrate Spring Boot 2 To Spring Boot 3'). Here in this article we will be talking about the step by step migration process to Spring Boot 3. Before getting into to the spring boot 3 migration process, you should go through any documentation to understand the important artifacts in the same. It always helps in minimizing any potential risk factor in the process. Let's start discussing 'How To Migrate Spring Boot 2 To Spring Boot 3'. Spring Boot 3 Migration: How To Migrate Spring Boot 2 To Spring Boot 3? Let's go through step by step