Using Resilience4j with Spring Boot Java

Spring Boot @Primary — Resolve multiple bean conflicts ⚡ Ever seen this error? “No qualifying bean of type found” ❌ Happens when: 👉 Multiple beans of same type exist Solution 👇 @Primary public class MyServiceImpl implements MyService {} 💡 What it does: Marks default bean when multiple exist Alternative: 👉 Use @Qualifier ⚠️ Mistake: Not handling multiple beans properly 👉 Leads to runtime errors Clean DI = stable application 🔥 #SpringBoot #Java #DependencyInjection

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

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

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

🚀 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

⚡ Multithreading in Java — Why It Matters In real-world applications, performance is everything. Multithreading allows Java applications to execute multiple tasks simultaneously instead of running them one by one. 📌 Why it’s important: → Improves application performance → Efficient CPU utilization → Handles multiple users/requests at the same time 💡 Common use cases: ✔️ Web servers handling multiple requests ✔️ Background tasks (logging, file processing) ✔️ Real-time systems ⚠️ But it also introduces challenges: → Synchronization issues → Race conditions → Deadlocks Understanding multithreading is not just about creating threads — it’s about writing safe and efficient concurrent code. #Java #AdvancedJava #Multithreading #BackendDevelopment #SoftwareEngineering

🚀 For Loop Example (Java) The `for` loop is used to execute a block of code a specific number of times. It consists of three parts: initialization, condition, and increment/decrement. The initialization initializes a loop counter variable. The condition is evaluated before each iteration, and the loop continues as long as the condition is true. The increment/decrement updates the loop counter after each iteration. This structure makes the `for` loop ideal for iterating over arrays or performing tasks a fixed number of times. #Java #JavaDev #OOP #Backend #professional #career #development

Learnt about multi threading in Java, making a thread, runnable interface, starting/pausing/interrupting/joining it. Concurrency issues when modifying a shared resource : race condition/ visibility issue. Solutions to race condition and visibility issue : confinement, locks, synchronize, volatile, etc. Multi threading is a feature that utilizes a CPU with multiple cores to create efficient software, think about downloading 5 files one after another or in parallel, impact is huge #Learner #JAVA #BACKEND

#Day14🔒 ReentrantLock vs synchronized — what’s the difference? synchronized is simple, but ReentrantLock gives more control 💡 👉 tryLock() → avoid waiting 👉 Fairness → FIFO locking 👉 Interruptible locks Example 👇 ReentrantLock lock = new ReentrantLock(); lock.lock(); try { // critical section } finally { lock.unlock(); } 💡 Rule: Always release lock in finally 👉 Use ReentrantLock when you need advanced control over threads #Java #Multithreading #ReentrantLock #Concurrency #JavaDeveloper #ThreadSafety #InterviewPreparation #LearningInPublic

⚠️ Deadlocks in Java — Small mistake, big problem. Deadlock occurs when two threads wait on each other forever. Thread 1 → holds Lock A, waiting for Lock B Thread 2 → holds Lock B, waiting for Lock A And the application just… freezes. 💡 How to avoid it: → Always follow a consistent lock order → Avoid unnecessary nested locks → Use tryLock() with timeout → Prefer high-level concurrency APIs Multithreading is not just about performance — it’s about writing safe and predictable code. #Java #Multithreading #Deadlock #Concurrency #BackendDevelopment