Aman Dhankhar’s Post

@Autowired isn’t removed — it’s just optional now. Spring Boot supports constructor injection automatically, helping us write cleaner and more testable code. Here’s a quick breakdown of what changed and modern best practices 👇 Article Link -> https://lnkd.in/gniXM5qJ #SpringBoot #Java #CleanCode

Spring Boot dependency injection (DI) pitfalls I learned building my first REST API: Don't rely on field injection blindly-use constructors for immutability and testability. Scenario: Multiple beans of the same type? @Qualifier saves the day. @Autowired @Qualifier('taskServiceImpl') private TaskService taskService; Pro tip: @Configuration + @Bean for custom wiring. Deployed my task manager CRUD in 20 mins-zero null pointers. Reduced boilerplate by 60%. Try it on your next project! Thoughts? #SpringBoot #Java #BackendDev

Today I refreshed my core Spring Framework concepts, especially focusing on XML-based configuration and Dependency Injection fundamentals. Here’s a quick summary of what I revised and practiced: 🔹 Setter Injection Learned how Spring injects dependencies using setter methods via XML configuration. 🔹 Constructor Injection Understood how dependencies are provided through constructors, making beans immutable and ensuring mandatory dependencies are set at object creation. 🔹 Injecting Non-Primitive (Object) Fields in XML If a field is a non-primitive type (i.e., another object), we use the ref attribute inside <property> or <constructor-arg> to reference another bean defined in the XML. 🔹 Autowiring in XML byName → Matches bean property name with bean id. byType → Matches bean property type with a single bean of the same type. 🔹 @Primary Bean When multiple beans of the same type exist, @Primary helps Spring decide which one to inject by default. 🔹 Lazy Initialization (lazy-init) Using lazy-init="true" to delay bean creation until it is actually needed, improving startup performance. Refreshing these fundamentals strengthens my understanding of how the Spring IoC container manages objects and dependencies behind the scenes. Mastering core concepts always makes advanced topics much easier 🚀 #SpringFramework #Java #DependencyInjection #BackendDevelopment #Learning #ComputerScience #FreshGraduate #javadeveloper #springboot

🔥 DAY 2 **How Spring Boot Dependency Injection actually works (Simple explanation)** Most developers use @Autowired. Few understand what happens behind the scenes. Here’s what Spring does: • Scans components • Creates beans in ApplicationContext • Manages lifecycle • Injects dependencies via constructor/setter Why it matters? Because: * It improves testability * Reduces tight coupling * Makes large systems manageable Framework knowledge is good. Understanding internals is better. #SpringBoot #Java #BackendDevelopment

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

Hello Connections 👋 While revisiting some Spring Boot basics recently, I came across something simple but quite useful — how to see all the beans managed by the Spring container. There are actually a couple of easy ways to do this: 👉 1. Using Spring Boot Actuator Just expose the beans endpoint in application.properties: management.endpoints.web.exposure.include=beans Then hit: /actuator/beans You’ll get a detailed view of all beans along with their dependencies. This is really helpful when you want to understand what Spring is creating behind the scenes. 👉 2. Using ApplicationContext programmatically You can also fetch all bean names directly from the container: String[] beanNames = applicationContext.getBeanDefinitionNames(); for (String beanName : beanNames) { System.out.println(beanName); } I found this especially useful while debugging and understanding auto-configuration behavior. If you’ve used any other way to inspect Spring beans, would love to know! #SpringBoot #Java #BackendDevelopment #Learning

Have you ever wondered how Spring Boot injects dependencies ? “Spring injects dependencies automatically.” But very few can explain HOW. Here’s what really happens behind the scenes: 1- Spring scans your classes 2- It creates BeanDefinitions 3- The ApplicationContext instantiates beans 4- Dependencies are resolved via constructor/setter injection 5- Beans go through the full lifecycle (init → post-processors → ready) Dependency Injection is not magic. It’s a container managing object graphs for you. If you understand: • Bean lifecycle • Singleton vs prototype scope • BeanPostProcessor • ApplicationContext vs BeanFactory You’re already thinking beyond annotations. I just broke it all down step by step https://lnkd.in/ewNmUK5b #SpringBoot #SpringFramework #Java #BackendDevelopment #SoftwareArchitecture

Java 21+ Features Hack 🚀 Java devs, if you're still on Java 17 or earlier in 2026, you're missing game-changers from Java 21+! I just refactored a legacy Spring Boot microservice using Virtual Threads (Project Loom) and pattern matching in switch expressions — load times dropped 40%, and my code went from 200+ lines to under 100. Here's a quick breakdown: Virtual Threads: No more blocking I/O nightmares. Thread.ofVirtual().start(() -> { /* your async magic */ }); handles thousands of concurrent requests without thread pool exhaustion. Records + Pattern Matching: if (obj instanceof Point(int x, int y)) { return x + y; }—bye-bye verbose getters/setters! Sequenced Collections: List.of(1,2,3).getFirst() and getLast() for cleaner list ops. Pro tip: Pair this with Spring Boot 3.3 for auto-config magic. Who's experimenting with these? Drop your wins or gotchas below—I’m all ears! #Java21 #SpringBoot #BackendDev #java #knowledge #Features

📌 Spring Boot Annotation Series – Part 2 ✅ @ComponentScan Ever faced a situation where Spring says ❌ NoSuchBeanDefinitionException even though your class is annotated correctly? That’s where @ComponentScan comes in 👇 🔹 WHY do we use @ComponentScan? Spring needs to know where your classes are. @ComponentScan tells Spring: 👉 “Scan these packages and create beans from them.” Without scanning, Spring doesn’t even see your classes. Spring needs to scan packages to find classes annotated with: @Component @Service @Repository @Controller 🔹 WHEN do we need @ComponentScan? When your service or config class is in a different package. When working on multi-module projects. When Spring can’t find a bean at runtime. 🔹 WHERE does Spring scan by default? By default, Spring scans: 👉 The package of the main application class 👉 And all its sub-packages If your class is outside this, Spring will miss it. @ComponentScan(basePackages = "com.example.app") #SpringBoot #Java #BackendDevelopment #LearningInPublic

TIL about Spring’s @ExceptionHandler selection rules — and it surprised me a bit. Quick summary: Inside the same @ControllerAdvice: root exception match > cause match Across different advice beans: @Order priority beats everything — even root vs cause. So a higher-priority advice matching a cause can override a lower-priority advice matching the actual exception. Lesson learned: Put your primary/global exception handlers in a high-priority @ControllerAdvice. Sharing in case it saves someone else a debugging session 🙂 #SpringBoot #Java