Resolve Spring Boot Bean Conflicts with @Primary

Spring Boot @Conditional — Hidden superpower ⚡ You can load beans conditionally! Examples: ✅ @ConditionalOnProperty ✅ @ConditionalOnMissingBean ✅ @ConditionalOnClass 💡 Use case: Load bean ONLY when needed Example: @Configuration @ConditionalOnProperty(name="feature.enabled", havingValue="true") 👉 Feature toggles made easy 🔥 ✔ Better flexibility ✔ Environment control ✔ Cleaner configs Most developers don’t use this — big mistake ❌ #SpringBoot #Java #BackendDeveloper

Spring Boot HandlerExceptionResolver — Advanced error handling 🔥 Most devs use @ControllerAdvice… but there’s a deeper layer 👇 👉 HandlerExceptionResolver It gives full control over: ✔ Exception handling ✔ HTTP response ✔ Error mapping 💡 Why use it? ✔ Fine-grained control ✔ Custom framework-level handling ⚠️ Use case: When @ExceptionHandler is not enough 👉 Example: Handle all exceptions globally with custom logic This is how frameworks are built internally 💯 #SpringBoot #Java #ExceptionHandling

🚀 Using Resilience4j with Spring Boot (Java) To use Resilience4j in a Spring Boot application, include the `resilience4j-spring-boot2` dependency. Annotate your methods with `@CircuitBreaker` to enable the circuit breaker functionality. Configure the circuit breaker properties in your `application.properties` or `application.yml` file, such as the failure rate threshold, the slow call rate threshold, and the wait duration in open state. This allows you to control the behavior of the circuit breaker. #Java #JavaDev #OOP #Backend #professional #career #development

The main class is the entry point  of the Spring Boot application. It contains  the @SpringBootApplication annotation and  starts the embedded  server using SpringApplication.run().. . . . . . . . . . #Java #JavaProgramming #JavaDeveloper #JavaCode #JavaScript #JavaCommunity #JavaTutorial #JavaLearning #JavaDevelopment #JavaLife #JavaLovers #JavaProjects #JavaCoding #JavaTips #JavaFramework #Java8 #JavaEE #JavaForBeginners #JavaGeek #JavaWorld #hackforge

What is @RestController in Spring Boot? 🚀 It is a combination of: @Controller + @ResponseBody 👉 It directly returns JSON response Example: @RestController public class Test {   @GetMapping("/hello")   public String hello() {     return "Hello";   } } Simple, clean, and perfect for APIs. Are you using Spring Boot in your project? #SpringBoot #Java #BackendDeveloper

Spring Boot @Bean vs @Component — Hidden difference 🔥 Both create beans… but NOT the same 👇 ✅ @Component - Auto-detected via component scan - Used for your own classes ✅ @Bean - Defined manually inside @Configuration - Used for third-party classes Example: @Bean public ObjectMapper objectMapper() { return new ObjectMapper(); } 💡 Why it matters: ✔ Better control over bean creation ✔ Custom configuration 👉 Use @Bean when you need flexibility Small concept → big design impact 💯 #SpringBoot #Java #Backend

🚀 Spring Boot Tip: @Qualifier vs @Primary (Fix Bean Ambiguity) Facing this error? 👇 "NoUniqueBeanDefinitionException" 👉 It means Spring found multiple beans of the same type and doesn’t know which one to inject. --- ✅ @Qualifier — Be Explicit Use "@Qualifier" when you want to specifically choose a bean. @Autowired @Qualifier("upiPaymentService") private PaymentService paymentService; ✔ You tell Spring exactly which implementation to inject ✔ Best when you have multiple beans and need control --- ✅ @Primary — Set a Default Use "@Primary" to mark one bean as the default choice. @Component @Primary class CreditCardPaymentService implements PaymentService {} ✔ Spring will pick this automatically ✔ Works when no "@Qualifier" is specified --- 🧠 Key Difference 👉 "@Qualifier" = Explicit selection 👉 "@Primary" = Default fallback --- ✨ Pro Tip If both are present: ➡️ "@Qualifier" overrides "@Primary" --- #SpringBoot #Java #BackendDevelopment #CodingTips #SoftwareEngineering

🚨 Spring Boot Trap @Transactional looks simple. But it has rules. It works when: • Called from another bean • Public methods • Proxy is active It fails silently when: • Self-invocation • Wrong propagation • Async methods Result? Data inconsistency. Always test transaction boundaries. Don’t assume they work. #SpringBoot #Java #Transactions #Backend #BackendDevelopment #JavaDeveloper #SoftwareEngineering #TechTips #SoftwareEngineer

🚀 Observer Pattern Example (Java) This example demonstrates the Observer pattern. The `Subject` class maintains a list of `Observer` objects and notifies them when its state changes. The `ConcreteObserver` class implements the `Observer` interface and updates its state when notified by the `Subject`. The `Subject` and `Observer` classes are loosely coupled, meaning that they can be changed independently of each other. This promotes flexibility and maintainability. Learn more on our app: https://lnkd.in/gefySfsc #Java #JavaDev #OOP #Backend #professional #career #development

Every Spring Boot developer should know this. The Bean Lifecycle - from start to destroy: 1. App starts → Spring boots up the IOC container 2. Spring reads your @Component / @Bean / @Configuration classes 3. Constructor is called → Bean is created 4. Dependencies are injected (@Autowired) 5. @PostConstruct runs → your init logic 6. Bean is live → handling requests 7. On shutdown → @PreDestroy runs, cleanup happens 8. Bean is destroyed #SpringBoot #Java #JavaDeveloper #BackendDevelopment #SpringFramework