Spring Bean Lifecycle: Creation to Destruction

🚀 Built my first REST API using Spring Boot This week I implemented a basic REST API as part of my backend development journey. What I built: • CRUD operations (Create, Read, Update, Delete) • API endpoints using Spring Boot • Structured code using Controller, Service, Repository layers Tech used: • Java • Spring Boot • Spring Web Key learning: Understanding how backend systems handle client requests using HTTP methods (GET, POST, PUT, DELETE) was a big step forward. Next step: Connecting this API with a database. #SpringBoot #RESTAPI #Java #BackendDevelopment #Coding

One thing I’ve learned working on high-volume backend systems: Concurrency is where Java really shines — but also where mistakes are costly. While building Spring Boot microservices, handling multiple requests efficiently requires more than just threads. A few things that made a real difference in my experience: • Using thread pools instead of unmanaged threads • Avoiding shared mutable state wherever possible • Leveraging asynchronous processing for non-blocking workflows • Monitoring thread usage and system load under peak traffic With newer Java versions, improvements in concurrency (like virtual threads) are making scalable systems even more efficient. Writing concurrent code is powerful — but it demands discipline and careful design. #Java #Concurrency #SpringBoot #BackendEngineering #DistributedSystems

Java Full Stack - Week 7 Progress Update Continuing my journey into the Spring ecosystem after understanding the core concepts last week. This week was focused on strengthening my understanding of how Spring actually works under the hood. Revisited and practiced: Spring IoC container and dependency management Dependency Injection in practice Using @Autowired and @Qualifier correctly Understanding how the Spring Bean lifecycle works inside the container Exploring how Spring configuration ties everything together Spending time on these fundamentals made it clearer how Spring simplifies application architecture by managing object creation and dependencies. Rather than rushing into advanced tools, the focus was on making sure the foundation concepts are clear. Next focus: Applying Spring concepts in real applications Moving into Spring Boot Building structured backend services using the Spring ecosystem Still progressing one layer at a time. #Java #SpringFramework #JavaFullStack #BackendDevelopment #LearningInPublic

Instead of only reading about Java, I decided to learn it by actually building something. Lately, I’ve been experimenting more with the Java backend ecosystem, so I built a backend project to put things into practice. The application uses Spring Boot to structure the API, Spring Security for authentication, and PostgreSQL with jOOQ for database access. It also integrates AWS S3 for file storage and Spring Mail for sending order confirmation emails, with Docker Compose used to simplify the local development setup. It was a good opportunity to explore how the typical components of a Java backend fit together in practice. If you're interested in the architecture or implementation, the full project is on GitHub: https://lnkd.in/dQA8mFJT Always open to feedback from other developers. #Java #BackendDevelopment #SpringBoot #LearningByBuilding

🚀 What Actually Happens When a Spring Boot Application Starts? Most developers just run the app and see: "Started Application in 3.2 seconds" But inside the JVM, a lot more is happening 👇 1️⃣ JVM Starts The JVM launches and executes the "main()" method from the JAR. 2️⃣ Class Loading Begins Classes are loaded using: • Bootstrap ClassLoader • Platform ClassLoader • Application ClassLoader 3️⃣ Bytecode Verification JVM verifies bytecode to ensure security and correctness. 4️⃣ SpringApplication.run() Executes This initializes the Spring Application Context. 5️⃣ Component Scanning Spring scans the project for beans like: "@Controller" "@Service" "@Repository" "@Component" 6️⃣ Dependency Injection Spring connects all beans automatically. 7️⃣ AOP Proxies Created Spring creates proxies for features like logging, transactions, and security. 8️⃣ Embedded Server Starts Tomcat/Jetty starts and the application becomes ready to serve APIs. ⚡ Most startup errors occur during: • Bean creation • Dependency injection • Auto configuration • Missing environment properties Understanding this flow helps in debugging Spring Boot applications faster. 📌 Currently exploring Spring Boot internals and backend architecture. If you're learning Java & Spring Boot, let’s connect and grow together! 🤝 #Java #SpringBoot #JVM #BackendDevelopment #Programming

Most developers use Spring… but don’t fully understand what it’s actually doing under the hood. Here’s the reality 👇 Earlier, we used to create objects manually using new. That means we controlled everything — object creation, dependency wiring, lifecycle. But that approach leads to: ❌ Tight coupling ❌ Hard-to-test code ❌ Difficult maintenance Spring flips this completely. Instead of us controlling objects, Spring takes control — this is Inversion of Control (IoC). Now the container: ✔ Creates objects ✔ Injects dependencies ✔ Manages lifecycle And this is where Dependency Injection (DI) comes in. From experience and best practices: Constructor Injection → most reliable (preferred) Setter Injection → useful but optional Field Injection → avoid in real projects Another thing many people ignore is the Bean Lifecycle. A Spring Bean is not just created and used — it goes through: ➡ Creation ➡ Dependency Injection ➡ Initialization (@PostConstruct) ➡ Proxy wrapping (like @Transactional) ➡ Destruction (@PreDestroy) Understanding this is what separates: 👉 Someone who “uses Spring” vs 👉 Someone who can debug, design, and scale Spring applications If you're working on real-world backend systems, this is not optional knowledge. This is the foundation. #Spring #SpringBoot #Java #Backend #Microservices #IoC #DependencyInjection

📚 Learning Spring Boot Annotations Today I explored some important Spring Boot annotations that make backend development easier. Some of the most commonly used ones are: ✔️ @SpringBootApplication – Main entry point of the application ✔️ @Autowired – Used for dependency injection ✔️ @RestController – Creates REST APIs ✔️ @Service – Business logic layer ✔️ @Repository – Database layer Spring Boot simplifies Java development and helps build scalable backend applications faster. Always excited to learn and improve my development skills. 💻 #Java #SpringBoot #BackendDeveloper #LearningJourney #SoftwareDevelopment

We over-engineer early… and regret it later. I’ve done this more than once especially in backend services. You start with a simple Spring Boot service. But instead of solving what’s needed, you start preparing for what might come. So you add: • extra service layers • generic abstractions • configurable workflows • interfaces “just in case” It feels like good design. Until a few weeks later: • simple changes touch multiple layers 😓 • debugging becomes harder than expected 🔍 • half the flexibility is never even used What’s interesting modern Java is pushing in the opposite direction. Recent additions are encouraging simpler, more direct code: 🧱 Records → less boilerplate 🧵 Virtual threads → simpler concurrency 🔗 Structured concurrency → clearer parallel flows 🧠 Pattern matching → more readable logic All of these reduce accidental complexity not add to it. Most of the time, the better approach is: 👉 Build simple → validate → evolve Good systems don’t start perfect. They become well-designed over time. Curious to know what’s something you over-engineered that you’d do differently today? #SoftwareEngineering #Java #SpringBoot #BackendDevelopment #SystemDesign

🚀 Spring Boot Annotations Cheat Sheet for Developers While working with Spring Boot, annotations play a crucial role in simplifying configuration, dependency injection, REST APIs, and database interactions. Here is the quick cheat sheet of commonly used Spring Boot annotations that every backend developer should know. This can be useful for interview preparation, quick revision, or day-to-day development. Covers key annotations across: 🔹Core Spring Boot configuration 🔹REST API development 🔹Dependency Injection 🔹JPA & Database operations 🔹Request handling Having these annotations at your fingertips can significantly speed up development and improve code readability. Sharing this as a quick reference for fellow developers. Hope it helps! 💡 If you find it useful, feel free to save or share it with your network. #SpringBoot #Java #BackendDevelopment #FullStackDevelopment #JavaDeveloper #SpringFramework #SoftwareEngineering #CodingTips #DeveloperResources #TechLearning #InterviewPreparation