Spring Boot Study Notes

Application Properties and Profiles

How Spring Boot externalizes configuration through application.properties/yml, property precedence, and environment-specific profiles.

Authentication and Authorization in Spring

How Spring Security distinguishes proving identity (authentication) from granting access (authorization), covering roles, method security, and JWT-based statel…

Bean Scopes in Spring

Understand the difference between singleton, prototype, and web-aware bean scopes, and when scoped proxies are required.

Building Microservices with Spring Boot

How to design, discover, secure, and make resilient a set of independently deployable Spring Boot services using Spring Cloud.

Building REST Controllers

Learn how to build REST controllers in Spring Boot using @RestController, structure methods cleanly, and return well-formed HTTP responses.

Component Scanning

Learn how Spring discovers annotated classes on the classpath and registers them as beans, and how to control scan scope with filters.

Configuration Classes

Learn how @Configuration classes and @Bean methods provide explicit, programmatic bean wiring, and how to compose and conditionally activate them.

Database Migrations with Flyway

Learn how Flyway version-controls your schema with plain SQL migration scripts, integrates with Spring Boot, and keeps environments consistent.

Defining JPA Entities

Learn how to model database tables as Java classes using JPA annotations, covering identifiers, column mapping, and entity relationships.

Dependency Injection Explained

Learn how Spring's IoC container supplies objects with the collaborators they need, instead of letting objects build those collaborators themselves.

Exception Handling in Spring Boot

Learn how to handle errors gracefully in Spring Boot REST APIs using @ExceptionHandler, @ControllerAdvice, and structured error responses.

Logging in Spring Boot

How Spring Boot's default Logback-based logging works, including log levels, per-package configuration, and structured logging for production.

Querying with JPA

Go beyond basic repository methods to master JPQL, the Criteria API, pagination, and performance pitfalls like the N+1 select problem.

Repositories in Spring Data

Understand the Repository interface hierarchy in Spring Data — from Repository and CrudRepository to PagingAndSortingRepository and JpaRepository.

Request and Response Bodies

Learn how Spring Boot serializes and deserializes JSON request and response bodies using @RequestBody, @ResponseBody, and Jackson.

Request Mapping and Path Variables

Understand how Spring Boot maps HTTP requests to controller methods using @RequestMapping, HTTP-method shortcuts, and path variables.

Spring Beans and Annotations

Understand what a Spring bean is, how stereotype annotations declare them, and how lifecycle and qualifier annotations control their behavior.

Spring Boot Actuator

How Spring Boot Actuator exposes production-ready monitoring endpoints for health checks, metrics, and application internals.

Spring Boot Auto-Configuration

How Spring Boot inspects the classpath and existing beans to automatically configure sensible defaults, and how to customize or override them.

Spring Boot Interview Questions

A curated walkthrough of the Spring Boot interview questions that come up most often, from auto-configuration internals to system-design judgment calls.

Spring Boot Project Structure

How a typical Spring Boot project is organized on disk, from Maven/Gradle build files to source packages and resources.

Spring Boot Quick Reference

A condensed cheat sheet of the most-used Spring Boot annotations, configuration patterns, Actuator endpoints, and CLI commands.

Spring Boot Starters

How starter dependencies bundle coherent, version-compatible sets of libraries so you can add capabilities like web or data access with one line.

Spring Boot with Docker

How to containerize Spring Boot applications using Dockerfiles, layered JARs, Cloud Native Buildpacks, and Docker Compose for local development.