sharankumar Rathod’s Post

🚀 Day 4 — How Spring Creates Objects (Constructor Injection 🔥) Till now I learned IoC & DI… Today I understood how Spring actually creates objects 👇 ❗ Before Spring: We create objects manually → tight coupling User u = new User("Ashish", "123", "ashish@gmail.com"); ❌ 💡 With Spring (Constructor Injection): 👉 Spring creates object + injects values ✅ 1. User.java (Model Class) 👉 Contains: variables + constructor + display method ✅ 2. applicationContext.xml (Spring Config File) 👉 Contains: bean definition + constructor injection <bean id="user" class="User"> <constructor-arg value="Ashish"/> <constructor-arg value="12345"/> <constructor-arg value="ashish@gmail.com"/> </bean> ✅ 3. Test.java (Main Class / IoC Start) 👉 Contains: start Spring container + get object ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); User user = (User) context.getBean("user"); user.display(); 🔍 What Spring did? Created User object Called constructor Injected values automatically 🔍 What is happening internally? 👉 ApplicationContext (IoC container): Creates beans (objects) Manages them Injects dependencies ⚡ Why Constructor Injection? Loose coupling Mandatory dependency (safe) Easy to test 💡 One simple understanding: 👉 We don’t create objects… Spring creates and connects them 💬 Did you try constructor injection in your project yet? Day 4 done ✅ #Spring #Java #BackendDevelopment #LearningInPublic #30DaysOfCode #SpringBoot #Developers

Topic of the day Dependency Injection? What is Dependency Injection (DI)? Dependency Injection (DI) is a concept where a class does not create its own dependencies, instead those dependencies are provided from outside. This helps in reducing tight coupling between classes and makes the code more flexible. For example, if a Car needs an Engine, instead of creating it using new Engine(), we pass the Engine object from outside: class Car { Engine engine; Car(Engine engine) { this.engine = engine; } } Why do we use Dependency Injection? Dependency Injection makes our code: =>Flexible (easy to change implementations) =>Maintainable (less impact when modifying code) =>Testable (we can use mock objects) How it works in Spring Boot? In Spring Boot, the IOC container handles Dependency Injection. When the application starts, Spring creates objects (beans) for classes annotated with @Component, @Service, etc., and injects them wherever needed. Types of Dependency Injection? # Constructor Injection – Dependencies are provided through constructor # Setter Injection – Dependencies are set using setter methods # Field Injection – Dependencies are injected directly using @Autowired Which is Best? Constructor Injection is considered the best approach because: It ensures all dependencies are available at object creation,Prevents null issues, makes unit testing easier. #java #spring #springboot #leraning #javadevelopment #microservices #kafka #hibernate #jpa

💡 Types of Dependency Injection in Spring – Setter Injection vs Constructor Injection Dependency Injection is one of the core concepts of the Spring Framework that helps developers build loosely coupled, flexible, and maintainable applications. Among the various types of dependency injection, Setter Injection and Constructor Injection are the most commonly used approaches. 🔹 Setter Injection Setter Injection is achieved using setter methods. In this approach, the Spring container creates the object first and then injects the required dependencies through setter methods. This method provides more flexibility, because dependencies can be modified or updated later if required. However, one drawback is that an object might be created without all required dependencies, which could lead to incomplete initialization. 🔹 Constructor Injection Constructor Injection is performed through the constructor of a class. In this method, all required dependencies are provided at the time of object creation. This ensures that the object is fully initialized from the beginning, making the application more robust and reliable. It also supports immutability, since dependencies cannot be changed after the object is created. • Setter Injection → Flexible → Dependencies can be changed later • Constructor Injection → Mandatory dependencies → More secure and reliable 🚀 In real-world applications, Constructor Injection is generally preferred for required dependencies, while Setter Injection is useful for optional configurations. Understanding these approaches helps developers design clean architecture and build efficient Spring applications. Thanks to Anand Kumar Buddarapu sir for the valuable guidance and clear explanation of these concepts. #SpringFramework #Java #DependencyInjection #ConstructorInjection #SetterInjection

🚀 Internal Working of IOC (Inversion of Control) in Spring. Understanding how Spring manages your application behind the scenes 👇 📌 Step-by-Step Flow: 1️⃣ Configuration Loading → Spring reads config (@Component, @Bean, etc.) 2️⃣ Bean Definition → Classes are identified & metadata is created 3️⃣ IOC Container → ApplicationContext initializes 4️⃣ Bean Creation → Objects created by Spring (no "new") 5️⃣ Dependency Injection → Dependencies injected (@Autowired) 6️⃣ Initialization → Init methods called (@PostConstruct) 7️⃣ Ready to Use → Bean is fully configured ✅ 8️⃣ Lifecycle Management → Create → Use → Destroy 9️⃣ Destruction → Cleanup (@PreDestroy) 💡 In Short: Spring handles object creation & dependencies, you focus only on business logic! ✨ IOC = Less effort, more control #Java #SpringBoot #SpringFramework #IOC #DependencyInjection #BackendDevelopment #Coding #InterviewPreparation

🚀 Dependency Injection in Spring –(Constructor & Setter Injection) In the Spring Framework, Dependency Injection (DI) is a core concept used to build flexible and loosely coupled applications. 🧩 What is Dependency Injection? (Detailed Definition) Dependency Injection is a design pattern in which: The required dependencies of a class are provided from outside by the Spring container, instead of being created inside the class. 👉 In simple words: A class does not create the objects it needs — it receives them from the container. 🧠 Why Dependency Injection is Important Without DI: Classes create their own dependencies Leads to tight coupling Difficult to modify and test With DI: ✔️ Promotes loose coupling ✔️ Improves code reusability ✔️ Makes testing easier ✔️ Enhances maintainability ⚙️ How Dependency Injection Works in Spring Spring IoC container starts It creates all objects (called beans) It identifies dependencies in each class Injects required dependencies Manages object lifecycle 🔍 Types of Dependency Injection 1️⃣ Constructor Injection 📖 Definition: In Constructor Injection, dependencies are provided to a class through its constructor at the time of object creation. 🧠 Explanation: A constructor is used to initialize the object All required dependencies are passed as parameters The object is created only when all dependencies are available 🎯 Characteristics: ✔️ Ensures mandatory dependencies are provided ✔️ Object is created in a fully initialized state ✔️ Promotes immutability (dependencies cannot be changed later) ✔️ Safer and more reliable ⚠️ Limitation: Not suitable for optional dependencies Can become complex if too many dependencies are required 2️⃣ Setter Injection 📖 Definition: In Setter Injection, dependencies are provided using setter methods after the object is created. 🧠 Explanation: Object is created first (empty state) Dependencies are injected later using setter methods Allows modifying dependencies anytime 🎯 Characteristics: ✔️ Supports optional dependencies ✔️ More flexible than constructor injection ✔️ Dependencies can be changed at runtime ⚠️ Limitation: Object may remain in an incomplete state if dependency is not set Less safe compared to constructor injection 🎯 When to Use What? 👉 Use Constructor Injection when: Dependency is mandatory Object must be fully initialized 👉 Use Setter Injection when: Dependency is optional You need flexibility to change it ✨ Conclusion Dependency Injection is a fundamental concept in Spring that separates object creation from business logic, making applications more modular and maintainable. #Java #SpringFramework #DependencyInjection #BackendDevelopment #SoftwareEngineering #Coding thanks to: Anand Kumar Buddarapu Saketh Kallepu Uppugundla Sairam

🚀 Types of Dependency Injection in Spring: Setter vs Constructor Injection As I continue exploring the Spring Framework, understanding how dependencies are injected is crucial for building clean and maintainable applications. Let’s dive into the two main types of Dependency Injection in Spring 👇 🔧 1. Setter Injection Setter Injection is a method where dependencies are injected using setter methods. 👉 Spring container calls the setter method to assign the dependency after the object is created. 📌 Example Concept: A Student class receives an Address object using a setter method. 💡 Key Points: ✨ Provides flexibility to change dependencies anytime ✨ Useful for optional dependencies ✨ Improves readability with clear method names ⚠️ Limitation: ❌ Object can remain in an incomplete state if dependency is not set 🏗️ 2. Constructor Injection Constructor Injection is a method where dependencies are injected through the constructor at the time of object creation. 👉 Dependencies are provided when the object is instantiated. 📌 Example Concept: A Student class receives an Address object via constructor. 💡 Key Points: ✨ Ensures all required dependencies are available at object creation ✨ Promotes immutability (no changes after creation) ✨ Recommended for mandatory dependencies ⚠️ Limitation: ❌ Less flexible if you need to change dependencies later 🔥 Setter vs Constructor Injection ✨ Setter Injection → Flexible & Optional ✨ Constructor Injection → Safe & Mandatory 💡 Final Thought: In real-world applications: 👉 Use Constructor Injection for required dependencies 👉 Use Setter Injection for optional dependencies Mentor, Anand Kumar Buddarapu sir.

🚀 Types of Dependency Injection in Spring: Setter vs Constructor Injection As I continue exploring the Spring Framework, understanding how dependencies are injected is crucial for building clean and maintainable applications. Let’s dive into the two main types of Dependency Injection in Spring 👇 🔧 1. Setter Injection Setter Injection is a method where dependencies are injected using setter methods. 👉 Spring container calls the setter method to assign the dependency after the object is created. 📌 Example Concept: A Student class receives an Address object using a setter method. 💡 Key Points: ✨ Provides flexibility to change dependencies anytime ✨ Useful for optional dependencies ✨ Improves readability with clear method names ⚠️ Limitation: ❌ Object can remain in an incomplete state if dependency is not set 🏗️ 2. Constructor Injection Constructor Injection is a method where dependencies are injected through the constructor at the time of object creation. 👉 Dependencies are provided when the object is instantiated. 📌 Example Concept: A Student class receives an Address object via constructor. 💡 Key Points: ✨ Ensures all required dependencies are available at object creation ✨ Promotes immutability (no changes after creation) ✨ Recommended for mandatory dependencies ⚠️ Limitation: ❌ Less flexible if you need to change dependencies later 🔥 Setter vs Constructor Injection ✨ Setter Injection → Flexible & Optional ✨ Constructor Injection → Safe & Mandatory 💡 Final Thought: In real-world applications: 👉 Use Constructor Injection for required dependencies 👉 Use Setter Injection for optional dependencies Mentor, Anand Kumar Buddarapu sir.

Day 7: Mastering Dependency Injection Architectures in Spring 🚀 I’m officially one week into my Spring Framework journey! Today was a deep dive into the core of how Spring manages object dependencies. Understanding the "How" and "When" of Dependency Injection (DI) is a game-changer for writing clean, maintainable code. Here are my key takeaways from today’s session on Setter vs. Constructor Injection: 🔹 Setter Injection: Uses <property> tags in XML and requires setter methods in your bean class. Pro-tip: This is the preferred choice when your bean has a large number of properties (e.g., 10-12), as it avoids creating massive, unreadable constructors. 🔹 Constructor Injection: Uses <constructor-arg> tags and requires a parameterized constructor. Pro-tip: This is ideal for mandatory dependencies or when you have only a few properties (e.g., 2-3) to keep your code concise. ⚠️ Did you know? If you configure both Setter and Constructor injection for the same property, Setter Injection wins. This is because the IOC container first creates the object via the constructor and then calls the setter method, effectively overriding the initial value. 🛠️ Moving Toward Modern Configs: I also explored XML + Annotation-driven configurations. By using <context:component-scan> and the @Autowired annotation, we can let Spring handle the heavy lifting of injection automatically on fields, setters, or constructors. This significantly reduces the boilerplate XML code! Every day, the "magic" of Spring becomes a little more clear. Onward to Day 8! #SpringFramework #JavaDeveloper #BackendDevelopment #LearningJourney #SoftwareEngineering #DependencyInjection #CodingCommunity #TechLearning

Last weekend I’ve been studying more about error handling and I watched a great video from Dan Vega — an interesting view on how to implement error handling and retries. 🚀 I pushed a small demo repo that captures those ideas using Spring Boot’s new RestClient and a clean error-handling pattern: 🔁 Retry transient failures with @Retryable (exponential backoff). 🧭 Centralize response-to-exception mapping via RestClient’s defaultStatusHandler (ApiException, NotFoundException). 🛡️ Serve consistent ProblemDetail (RFC 7807) responses from a GlobalExceptionHandler for clearer API errors. 🧪 Uses https://httpbin.org/ to simulate status codes and unstable endpoints for deterministic testing. Why this is valuable: - Increases reliability by handling transient errors consistently. - Keeps controllers and business logic clean — the client layer interprets remote errors. - Improves client experience with predictable, machine-readable error payloads. Inspired by Dan Vega’s walkthroughs — credit to him for the patterns and clarity. 🙏 Feel curious how that I did it, check the repo to see the config, examples, and how to adapt this pattern: https://lnkd.in/dEe3HNKr #SpringBoot #Java #Resilience #ErrorHandling #RestClient #Microservices

Architecture diagrams are useful until the code stops obeying them. This piece looks at a harder problem: how to make Java architecture boundaries executable with Quarkus, tests, and build-time feedback. The goal is not prettier diagrams. It is fewer silent boundary violations and less architectural drift. Useful if your architecture rules live in diagrams but not in feedback loops. https://lnkd.in/dTEQGJj8 #Java #Quarkus #SoftwareArchitecture