Mohit Salunke’s Post

🚀 30 Days of Spring Boot – Day 1 Today I covered the core fundamentals of Spring & Spring Boot 👇 🔹 What is Spring? A powerful Java framework used to build scalable and enterprise applications with features like IoC and DI. 🔹 What is Spring Boot? An extension of Spring that makes development faster with auto-configuration, embedded servers, and minimal setup. 🔹 IoC (Inversion of Control) Spring manages object creation and lifecycle instead of developers doing it manually. 🔹 Dependency Injection (DI) Dependencies are injected by Spring → making code loosely coupled and easy to test. 💡 Built a small project using: @Component @Service @Autowired ✔ Layered architecture (Controller → Service → Component) 📌 Key Learning: Don’t create objects manually — let Spring handle it! #SpringBoot #Java #BackendDevelopment #Microservices #LearningJourney #30DaysChallenge #Developers #Coding

#java #springboot #tips 🚫 Stop using field injection in Spring Boot. Here’s why: Most developers write this: @Autowired private UserService userService; ✅ Use constructor injection instead: @Service @RequiredArgsConstructor public class OrderService { private final UserService userService; // immutable + testable } Why it matters: • Fields are final → truly immutable • Easier to unit test without Spring context • Fails fast at startup if bean is missing • Works perfectly with Lombok’s @RequiredArgsConstructor This is also the official Spring recommendation since Spring 4.x. #Java #SpringBoot #CleanCode #BackendDev

🚀 Day 8 — Spring Bean Lifecycle (Complete Flow 🔥) Today I learned how Spring creates, manages, and destroys objects (Beans) 👇 💡 Bean Lifecycle (Simple Flow): 👉 Create Bean 👉 Inject Dependencies 👉 Initialize Bean 👉 Use Bean 👉 Destroy Bean ⚡ Important Annotations: @PostConstruct → runs after bean creation @PreDestroy → runs before bean destruction 🔍 What Spring does internally? 👉 IoC Container: Creates object Injects dependencies Manages lifecycle 💡 One simple line: 👉 Spring controls the entire life of an object 💬 Did you know Spring handles object destruction too? Day 8 done ✅ #Spring #Java #BackendDevelopment #LearningInPublic #30DaysOfCode #SpringBoot #Developers

Most people use Spring Boot. But very few understand what actually happens when the application starts While going deeper into it, a few things started making more sense How the application context is created What SpringBootApplication really triggers How the bean lifecycle actually works Why proxies are used for things like Transactional And how self invocation can silently break things It is easy to write Spring code Understanding what happens inside is different Still learning and connecting the dots What part of Spring feels confusing to you #Java #SpringBoot #BackendDevelopment #SoftwareEngineering #JavaDeveloper #SystemDesign #Placements

🚀 Learning Exception Handling in Spring Boot Today I worked on handling exceptions in a Spring Boot application to make APIs more robust and user-friendly. What I learned: • Why exception handling is important in backend systems • Using @ExceptionHandler for handling specific exceptions • Implementing @ControllerAdvice for global exception handling • Returning meaningful error responses instead of generic server errors 💡 Key takeaway: Proper exception handling improves API reliability and provides clear feedback to clients instead of exposing internal errors. 🎯 Next step: Integrating exception handling into my existing REST APIs. Small improvements like this make a big difference in real-world applications. #SpringBoot #Java #BackendDevelopment #ExceptionHandling #Coding

🚀 Mastering Spring Boot – Step by Step (Day 2) Still using "new" in Spring? ❌ 👉 Then you’re missing the core idea of Spring 💡 What is a Spring Bean? A Bean is: 👉 Any object managed by the Spring IoC container Instead of: UserService service = new UserService(); Spring does: ✔ Create objects ✔ Manage lifecycle ✔ Connect components 💡 What is IoC (Inversion of Control)? 👉 You don’t control object creation anymore 👉 Spring does it for you This leads to: ✔ Cleaner code ✔ Loose coupling ✔ Better scalability 💡 Simple way to think: You: "I will create objects" ❌ Spring: "I will handle everything" ✅ 👉 This is the foundation of Spring Next → Dependency Injection (real magic begins) 🔥 #Spring #SpringBoot #Java #Backend #LearningInPublic

Last week our Spring Boot service froze completely under load. No errors. No exceptions. Just requests piling up and users  seeing blank screens. Turns out it was thread pool exhaustion — one of the most  common production issues that looks nothing like what it is. I wrote a detailed breakdown of: → How we diagnosed it using thread dumps and Actuator metrics → Why adding timeouts was the immediate fix → How we properly solved it with async thread pool isolation → What to check in your own Spring Boot service right now Full article link in the comments 👇 If you are building Java microservices — this one is worth  bookmarking. #Java #SpringBoot #Backend #Microservices #SoftwareEngineering  #Programming #BackendDevelopment #TechBlog

🚀 Understanding Dependency Injection in Spring Boot As a Java Backend Developer, one concept that truly changed how I design applications is Dependency Injection (DI). 👉 What is Dependency Injection? Dependency Injection is a design pattern in which an object receives its dependencies from an external source rather than creating them itself. This helps in building loosely coupled, testable, and maintainable applications. Instead of: ❌ Creating objects manually inside a class We do: ✅ Let the framework (like Spring Boot) inject required dependencies automatically 💡 Types of Dependency Injection in Spring Boot 1️⃣ Constructor Injection (Recommended) Dependencies are provided through the class constructor. ✔ Promotes immutability ✔ Easier to test ✔ Ensures required dependencies are not null 2️⃣ Setter Injection Dependencies are set using setter methods. ✔ Useful for optional dependencies ✔ Provides flexibility 3️⃣ Field Injection Dependencies are injected directly into fields using annotations like @Autowired. ✔ Less boilerplate ❌ Not recommended for production (harder to test & maintain) 🔥 Why use Dependency Injection? ✔ Loose coupling ✔ Better unit testing ✔ Cleaner code architecture ✔ Easy to manage and scale applications 📌 In modern Spring Boot applications, Constructor Injection is considered the best practice. 💬 What type of Dependency Injection do you prefer and why? #Java #SpringBoot #BackendDevelopment #SoftwareEngineering #CleanCode #DependencyInjection

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

Most developers use Spring Boot… but very few actually understand it. That’s where the difference shows up in interviews and real projects. I just revised the most important Spring Boot annotations — and honestly, this is what every backend developer should know: Not just what @RestController does… But why you use it. Not just @Transactional… But when it saves your data from breaking. Not just @Autowired… But how dependency injection actually works behind the scenes. 💡 Real growth starts when you stop memorizing and start thinking like an engineer. If you’re serious about backend development, this is your foundation. 📌 Save this. Revisit it. Use it in your next project. #SpringBoot #JavaDeveloper #BackendDevelopment #SoftwareEngineer #Coding #Developers #Programming #Tech #LearnToCode #Java #SpringFramework #RESTAPI #JPA #Hibernate #CodingJourney #CareerGrowth #TechSkills