Boost API Development with @RestController in Spring Boot

I wrote 50 lines of code to do something that takes 4. Not because I was lazy. Because I didn't know there was a better way. Java Streams changed that. Before: → Loop → Check → Update → Return After: → .filter() → .map() → .collect() → Done. Same result. Half the code. Easier to read at 11pm. Spend 30% reading the API. Spend 70% writing the code. That's the ratio that builds real skill. Save this. Open your IDE. Find one loop. Convert it. That's your first rep. #JavaDeveloper #SoftwareEngineering #CleanCode

Day 03 Refining my Backend Skills via Projects Today I worked on Global Exception Handling in my Spring Boot Blog API project . What I implemented: • Created a custom ResourceNotFoundException • Added GlobalExceptionHandler using @RestControllerAdvice • Implemented @ExceptionHandler to return clean API error responses • Improved API responses using a custom ApiResponse class • Updated the Custom DTO to Model Mapper This helps make APIs more robust and production-ready by handling errors in a structured way . #Java #SpringBoot #BackendDevelopment #CodingJourney #100DaysOfCode

Why Spring Is Moving Back Toward Simplicity Reactive programming became popular because: - Threads were expensive - Blocking didn’t scale That led to code like this: Mono<User> user = service.getUser()   .flatMap(this::validate)   .flatMap(this::enrich); Powerful — but hard to: - Read - Debug - Maintain Virtual threads allow this again: User user = service.getUser(); validate(user); enrich(user); Same scalability. Much clearer flow. 💡 Takeaway: Spring and Java are converging toward readability. #Java #SpringBoot #BackendEngineering #Java25

🚀Handling Responses in Spring Boot Today I explored an important part of backend development — handling API responses properly. While building REST APIs, returning only data is not enough. The response should clearly communicate the result of the request using appropriate HTTP status codes. What I learned today: • Understanding common HTTP status codes (200, 201, 400, 404, 500) • How APIs use status codes to communicate success or errors • Using ResponseEntity<> in Spring Boot to control response body, status, and headers • Structuring cleaner API responses I also explored the basics of Lombok, which helps reduce boilerplate code in Java. Some useful Lombok annotations I learned: • @Getter and @Setter • @NoArgsConstructor and @AllArgsConstructor • @Data for cleaner model classes Learning how to return meaningful responses makes APIs clearer, more professional, and easier for clients to consume. Step by step, the backend is starting to feel more structured. #SpringBoot #BackendDevelopment #Java #RESTAPI #Lombok #SoftwareEngineering

𝗦𝘁𝗼𝗽 𝘂𝘀𝗶𝗻𝗴 @𝗔𝘂𝘁𝗼𝘄𝗶𝗿𝗲𝗱 𝗼𝗻 𝘆𝗼𝘂𝗿 𝗳𝗶𝗲𝗹𝗱𝘀. Today I want to talk about a topic that I learned on LinkedIn some time ago. When working with Spring Boot, most introductory courses teach dependency handling by the use of 𝗙𝗶𝗲𝗹𝗱 𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻. Even though it works for its purpose, you end up with a tight coupling between your class and the Spring Container. A much better option is to use 𝗖𝗼𝗻𝘀𝘁𝗿𝘂𝗰𝘁𝗼𝗿 𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻. By injecting your dependencies directly into your constructor, you get several improvements: - 𝗜𝗺𝗺𝘂𝘁𝗮𝗯𝗶𝗹𝗶𝘁𝘆: Dependencies are declared as 𝘧𝘪𝘯𝘢𝘭, which prevents runtime mutation and eliminates an entire class of potential bugs. - 𝗡𝘂𝗹𝗹 𝗦𝗮𝗳𝗲𝘁𝘆: Your class is only instantiated when all dependencies are provided. This avoids Field Injection’s 𝘕𝘶𝘭𝘭𝘗𝘰𝘪𝘯𝘵𝘦𝘳𝘌𝘹𝘤𝘦𝘱𝘵𝘪𝘰𝘯, which can only be identified at runtime. - 𝗕𝗲𝘁𝘁𝗲𝗿 𝘁𝗲𝘀𝘁𝘀: When working with Field Injection, you end up having to add a @𝘚𝘱𝘳𝘪𝘯𝘨𝘉𝘰𝘰𝘵𝘛𝘦𝘴𝘵 and use complex tools like Reflection. While for 𝗖𝗼𝗻𝘀𝘁𝗿𝘂𝗰𝘁𝗼𝗿 𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻, the creation of unit tests gets easier. You instantiate a service as a simple Java object declaration. This improves build and execution times significantly. Another great example on why Constructor Injection is a better option is how it handles 𝗖𝗶𝗿𝗰𝘂𝗹𝗮𝗿 𝗗𝗲𝗽𝗲𝗻𝗱𝗲𝗻𝗰𝗶𝗲𝘀. If 𝘚𝘦𝘳𝘷𝘪𝘤𝘦𝘈 depends on 𝘚𝘦𝘳𝘷𝘪𝘤𝘦𝘉, and 𝘚𝘦𝘳𝘷𝘪𝘤𝘦𝘉 depends on 𝘚𝘦𝘳𝘷𝘪𝘤𝘦𝘈, Field Injection might allow the application build and start, but eventually you would get a 𝘚𝘵𝘢𝘤𝘬𝘖𝘷𝘦𝘳𝘧𝘭𝘰𝘸𝘌𝘳𝘳𝘰𝘳. With 𝗖𝗼𝗻𝘀𝘁𝗿𝘂𝗰𝘁𝗼𝗿 𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻, you will get an error on startup, forcing you to fix the error and make sure you don’t release a hidden Exception to production. As an additional tip, you can use Lombok’s @𝘙𝘦𝘲𝘶𝘪𝘳𝘦𝘥𝘈𝘳𝘨𝘴𝘊𝘰𝘯𝘴𝘵𝘳𝘶𝘤𝘵𝘰𝘳 annotation, which creates the constructor for all your 𝘧𝘪𝘯𝘢𝘭 dependencies, which means a better and cleaner code. Are you still using Field Injection in your legacy projects, or have you updated them to Constructor Injection? #Java #SpringBoot #BackendDevelopment #SoftwareEngineering #SpringFramework

🚀 What is Dependency Injection in Spring Boot? While learning Spring Boot, one concept that really improved my understanding of backend development was Dependency Injection (DI). At first, the name sounded complicated, but the idea is actually simple. 👉 Dependency Injection means letting Spring create and manage objects instead of creating them manually. Without Dependency Injection UserService userService = new UserService(); Here the class is responsible for creating the object itself, which creates tight coupling. With Dependency Injection in Spring Boot @Autowired private UserService userService; Now Spring automatically creates and injects the object when the application starts. Why is Dependency Injection important? ✔ Reduces tight coupling between classes ✔ Makes code easier to test ✔ Improves maintainability ✔ Helps build scalable applications This is one of the key concepts that makes Spring Boot powerful for backend development. #Java #SpringBoot #BackendDevelopment #LearningInPublic #Coding

✍️ Handwritten → 💻 Digitized. My 30-Day Java Full Stack Blueprint is live! Consistency is key. Over the last month, I’ve been documenting every step of my Full Stack development path—from manual @RestController setups to complex useEffect dependency arrays. I’ve now converted all my handwritten scribbles into a clean, Markdown-formatted digital guide. This process didn't just help me share the notes; it reinforced every technical concept from Inversion of Control (IoC) to Virtual DOM efficiency. Key Topics Covered: 🔹 Spring Boot Annotations (@RequestBody, @PathVariable, etc.). 🔹 Connecting PostgreSQL with Spring JPA. 🔹 JavaScript Promises and the Fetch API. 🔹 React Components, Props, and State. If you're on a similar learning path, I hope this helps! Grab the digital version below. #SoftwareEngineering #Java #React #GitHub #TechCommunity #FullStackDeveloper

🚀 Day 50 – Building a URL Shortener with Spring Boot Today I implemented the core redirect functionality of my URL shortener backend. The system can now generate short URLs and redirect users to the original destination using HTTP redirects. The application now supports: • Creating short URLs through a REST API • Redirecting users to the original link using the generated short code • Structured backend architecture using Controllers, Services, DTOs, and Models While testing the API, I also handled endpoint mapping conflicts and refined the controller structure to ensure clean routing. This milestone completes the core functionality of a URL shortener service, similar to how platforms like Bitly work at a basic level. Tech Stack: Java • Spring Boot • REST APIs Consistent progress every day is slowly turning this project into a complete backend system. Looking forward to improving the architecture further in the coming days. #Java #SpringBoot #BackendDevelopment #100DaysOfCode #BuildInPublic

Hi everyone 👋 📌 Spring Boot Annotation Series Part 21 – @PathVariable @PathVariable is used to extract values from the URL path and bind them to method parameters. It is part of the Spring Framework and widely used in REST APIs built with Spring Boot. 🔹 Why Do We Use @PathVariable? In REST APIs, resources are identified using IDs in the URL. Example: GET /users/101 Here, 101 is part of the URL path. @PathVariable helps us capture that value inside the controller method. 🔹 Basic Example @RestController @RequestMapping("/users") public class UserController { @GetMapping("/{id}") public String getUserById(@PathVariable Long id) { return "User ID is: " + id; } } 👉 If request is: GET http://localhost:8080/users/101 Output: User ID is: 101 🔹 In Simple Words @PathVariable takes dynamic values from the URL and passes them to the controller method. #SpringBoot #Java #RESTAPI #PathVariable #BackendDevelopment #InterviewPreparation

🚀 Spring Framework 🌱 | Day 2 – Dependency Injection (DI) Today I understood Dependency Injection not just as a concept… but as a mindset shift 💡 👉 In real life, DI is everywhere. Think about this 👇 ☕ When you order tea in an office You don’t go to the kitchen, buy milk, sugar, tea powder and make it yourself. 👉 Someone provides it to you. 🚗 When you book a cab You don’t build the car or hire a driver manually. 👉 The system injects the service you need. 🏢 In a company project A developer doesn’t create every object manually. 👉 Framework like Spring injects dependencies automatically. 💡 Same happens in Spring Instead of: ❌ Creating objects using "new" We let Spring: ✅ Create objects ✅ Manage them ✅ Inject wherever needed 🔹 How it works internally (simple view): 👉 Spring scans classes 👉 Creates beans in IOC container 👉 Finds dependencies 👉 Injects them using annotations 🔥 Why this matters? - Loose coupling - Easy testing - Clean & scalable code 👉 Small concept, but it completely changes how you build applications. #SpringFramework #Java #BackendDevelopment #LearningJourney #SpringBoot #TechGrowth