Centralized Exception Handling in Spring Boot

🚀 Day 55/100 - Spring Boot - Logging Once your application is running in production, System.out.println() is not enough ❌ You need structured, configurable, and production-ready logging❗ For that, spring boot uses: 🔹SLF4J (Logging API / facade) 🔹Logback (Default implementation) ➡️ Why Logging Matters? Because it helps you: ✔ Monitor application behavior ✔ Debug issues in production ✔ Track errors ✔ Audit important events ✔ Analyze system health Good logging = easier debugging = better reliability ➡️ SLF4J and Logback 🔹 SLF4J (Simple Logging Facade for Java) 🔹It’s a logging abstraction 🔹Allows switching logging frameworks (Logback, Log4j, etc.) 🔹Spring Boot includes it by default Think of it as an interface for logging. ➡️ Basic Logging Example (see attached image 👇) ➡️ Different Log Levels & their Purpose TRACE: used for very detailed debugging DEBUG: used for development debugging INFO: used for general application events WARN: used for something unexpected ERROR: used for serious problems ➡️ Best Practices ✔ Use INFO for important business events ✔ Use WARN for suspicious behavior ✔ Use ERROR for failures ✔ Avoid excessive logging Previous post: https://lnkd.in/dZVkgwcD #100Days #SpringBoot #Logging #SLF4J #Logback #Java #BackendDevelopment #WebDevelopment #SoftwareEngineering

⚙️ 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝗖𝗼𝗻𝗳𝗶𝗴𝘂𝗿𝗮𝘁𝗶𝗼𝗻 𝗘𝘅𝗽𝗹𝗮𝗶𝗻𝗲𝗱 — 𝗖𝗼𝗺𝗽𝗹𝗲𝘁𝗲 𝗕𝗲𝗴𝗶𝗻𝗻𝗲𝗿 𝘁𝗼 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗚𝘂𝗶𝗱𝗲 Spring Boot configuration is the backbone of every Spring Boot application. It helps you manage application settings, environment variables, database connections, server ports, and much more — all in a clean and flexible way. 📌 What you’ll understand: ✔ What Spring Boot configuration is and why it matters ✔ application.properties vs application.yml ✔ Externalized configuration (env variables, command line, profiles) ✔ @Configuration and @Bean annotations ✔ Spring Profiles for different environments (dev, test, prod) ✔ Auto-configuration — how Spring Boot configures things automatically ✔ Best practices for scalable and maintainable configuration Mastering configuration helps you build production-ready, flexible, and environment-friendly Spring Boot applications with ease. 💡 Learn it once, use it in every Spring Boot project! #SpringBoot #SpringFramework #JavaDeveloper #BackendDevelopment #Configuration #Microservices #Java #SoftwareEngineering #Programming #Developers #TechLearning #ApplicationDevelopment #Coding

🚀 Spring Boot Annotations – The Backbone of Every Application Many developers use Spring Boot annotations every day, but very few truly understand where each annotation works internally. I created this simple visual guide to understand the most important Spring Boot annotations and their roles in the application flow. 🔹 @SpringBootApplication – Entry point of the Spring Boot application 🔹 @ComponentScan – Scans and detects Spring components 🔹 @Configuration / @Bean – Defines configuration and beans 🔹 @Controller / @RestController – Handles HTTP requests 🔹 @Service – Contains business logic 🔹 @Repository – Handles database operations 🔹 @Transactional – Manages database transactions 🔹 @Value / @PropertySource – Injects configuration values All these components come together inside the Application Context, which manages the lifecycle of every bean in a Spring Boot application. Understanding this flow helps developers: ✅ Write cleaner architecture ✅ Debug issues faster ✅ Master Spring Boot internals 📌 If you're learning Spring Boot, understanding annotations is the first step toward mastering the framework. #Java #SpringBoot #BackendDevelopment #JavaDeveloper #Programming #SoftwareDevelopment #SpringFramework #TechLearning #Coding Durgesh Tiwari Anshika Singh

Most developers write code. Few developers design for failure. Designing for failure means building systems that remain stable even when things go wrong. In real production systems, failures are normal: • External API timeouts • Database connection issues • Invalid user input • Network failures If exceptions are not handled properly, your system will crash — not scale. Crash means: • Sudden 500 errors • Application restarts • Broken user experience Scale means: • Handling more users smoothly • Recovering from failures gracefully • Staying stable under high traffic In Java + Spring Boot, good exception handling means: ✔️ Using @ControllerAdvice for global handling ✔️ Returning meaningful HTTP status codes ✔️ Logging errors properly ✔️ Never exposing internal stack traces Clean exception handling = Stable production systems. What’s the biggest production issue you’ve faced? 👇 #Java #SpringBoot #BackendDevelopment #Microservices #SoftwareEngineering

🚀 PUT vs PATCH in Spring Boot — Are You Using Them Correctly?🚀 One small mistake I often see in Spring Boot projects is mixing up PUT and PATCH in REST APIs, or even some programmers keep using other alternatives like POST. They both update data… but they are NOT the same. 🔁 PUT = Full Update or replacing the entire object. When using @PutMapping, you’re expected to send the entire object. If a field is missing, it may be overwritten or set to null, unless it should be not null which may cause errors. 🩹 PATCH = Partial Update With @PatchMapping, you update only the fields you send. Unsent fields remain unchanged. If you're building clean, scalable APIs: Use PUT for full updates Use PATCH for partial updates Clean APIs = predictable behavior = better maintainability. #SpringBoot #Java #RESTAPI #BackendDevelopment #SoftwareEngineering #linkedin #network #Development #Controllers

🚀 Spring Boot Series – Part 4: Spring Framework vs Spring Boot The Spring Framework introduced powerful concepts such as IoC (Inversion of Control) and DI (Dependency Injection), but developers often had to configure things manually before writing business logic. For example: • XML / Java configurations (<bean>, web.xml) • Adding each dependency separately (Core, MVC, Data, etc.) • Configuring database connections • Setting up external servers like Tomcat / Jetty This meant spending a lot of time configuring the project infrastructure. 💡 Spring Boot simplified this experience. With Spring Boot, we get: ✔ Auto-configuration – configuration is created automatically when dependencies are added ✔ Starter dependencies – one dependency bundles everything needed ✔ Embedded server – run applications directly as a JAR ✔ Sensible defaults – applications work with almost zero configuration ✔ Production-ready features – Actuator provides /health, /metrics, and much more ⚡ In simple terms: Spring Framework → Powerful but requires setup Spring Boot → Same power with faster development A good way to think about it: Spring Boot = Spring Framework + Auto-Configuration + Starter Dependencies + Embedded Server 💬 What was the biggest difference you noticed when moving from Spring to Spring Boot? #SpringBoot #SpringFramework #Java #BackendDevelopment #SoftwareEngineering #JavaDeveloper #Programming #TechCommunity

One Thing That Changed the Way I Write Spring Boot Code… While working with Spring Boot, I realized something important: Logging with SLF4J is not optional — it’s necessary. At first, I was just writing: • Controllers • Services • Repositories and testing APIs in Postman. If it worked → good. If it didn’t → confusion. Then I started adding logs using SLF4J. Logging when: • A request enters the controller • The service starts processing • Important values are being handled • An exception happens But another small habit helped even more. While writing unit tests, I started checking how the logs actually print. Later in production, the first thing we check is logs. If the log says: "Error occurred while processing request" Will that actually help debug the issue? Now I always ask during testing: • Does this log include useful context (IDs / inputs)? • Is the message clear enough for debugging? • Is the correct log level used (INFO / WARN / ERROR)? Good logs during development → Faster debugging in production. #SpringBoot #Java #SLF4J #UnitTesting #BackendDevelopment

🚀Spring Boot Internals Simplified — What Happens When a Request Hits Your API? 👩🎓Ever wondered what actually happens behind the scenes when you hit a Spring Boot endpoint? 📌Let’s break it down step-by-step 🔹 1. Client Sends Request Browser / Postman sends an HTTP request Example: POST /api/users 🔹 2. DispatcherServlet (The Traffic Controller) Spring Boot’s front controller routes the request to the correct handler using HandlerMapping 🔹 3. Controller Layer (@RestController) ✅Receives request ✅Validates input ✅Delegates work to Service layer 🔹 4. Service Layer (@Service) ☑️Where real business logic lives ☑️Performs validations, transformations ☑️Calls Repository 🔹 5. Repository Layer (JPA Repository) ➡️Interacts with database ➡️Executes SQL (auto-generated by Spring) 🔹 6. Response (JSON) 🔹Java object → JSON (via Jackson) 🔹Sent back with HTTP status (200 OK) 💡 Key Takeaways: ✔ Controller = Handles HTTP only (no business logic) ✔ Service = Brain of your application ✔ Repository = Only layer talking to DB ✔ Each layer = Single Responsibility (SRP) 🔥 If you understand this flow clearly, you already have a strong foundation in Spring Boot. 💬 What part of Spring Boot do you find most confusing? #SpringBoot #Java #parmeshwarmetkar #BackendDevelopment #SystemDesign #Coding #Tech #Learning

Day 15 – Spring Boot Architecture Deep Dive Today I focused on understanding the architecture of Spring Boot and how it works internally. =>Spring Boot simplifies Java backend development by reducing configuration and providing an opinionated setup for building applications. =>One of the core features is auto-configuration. When we add a starter dependency like spring-boot-starter-web, Spring Boot automatically configures the embedded server, Dispatcher Servlet, and required beans. This reduces manual setup and speeds up development. =>Another important concept is starter dependencies. Starters bundle commonly used libraries together, making dependency management easier and more consistent. =>Spring Boot also provides an embedded server (Tomcat by default). This allows the application to run as a standalone JAR file without external deployment, which makes development and testing faster. =>Most Spring Boot applications follow a layered architecture: Controller → Service → Repository → Database This separation of concerns improves code maintainability, scalability, and clarity. Understanding the internal architecture gives better confidence in building production-ready backend systems instead of just writing APIs. Learning beyond syntax. Learning the structure. #Day15 #SpringBoot #BackendDevelopment #Java #SoftwareArchitecture #LearningJourney

🔧 application.properties vs application.yml — Which one should you actually use in Spring Boot? After working on many Spring Boot projects, here's the real difference: application.properties — flat key-value, dead simple: server.port=8080 spring.datasource.url=jdbc:postgresql://localhost:5432/mydb spring.jpa.show-sql=true application.yml — hierarchical YAML, far more readable at scale: server: port: 8080 spring: datasource: url: jdbc:postgresql://localhost:5432/mydb jpa: show-sql: true What you need to know: ✅ YAML handles nested structures and lists much more cleanly ✅ Properties = simpler, zero indentation errors ✅ If BOTH files exist — properties takes precedence over yml ✅ YAML lets you define multiple profiles in ONE file using --- separator ✅ Never store secrets in either — use env vars or Vault My take: Use .yml for complex multi-profile apps. Use .properties for quick setups or when the team prefers flat configs. #Java #SpringBoot #BackendDevelopment #SoftwareEngineering #Programming