CodeInvestigator’s Post

🚀 Spring Boot Performance Tips: ✅ Use connection pooling ✅ Enable caching ✅ Optimize DB queries ✅ Use async processing Small changes → big performance gains. Which one made the biggest impact for you? #SpringBoot #Performance #Java

Spring Boot Configuration Order — Why your config sometimes doesn’t work 😅 Spring Boot loads configs in a specific priority: 1️⃣ application.properties 2️⃣ application-{profile}.properties 3️⃣ Environment variables 4️⃣ Command line args 💡 Important: 👉 Higher priority overrides lower ones ⚠️ Common issue: “Why is my config not working?” 👉 Because something else is overriding it! 🔥 Pro tip: Use Actuator → /env endpoint to debug configs Understanding this saves hours of debugging 🚀 #SpringBoot #Java #Configuration

Spring Boot Filters vs Interceptors — Most developers confuse this 🤯 Let’s simplify 👇 ✅ Filter (Servlet level) - Works BEFORE DispatcherServlet - Used for logging, authentication, request modification ✅ Interceptor (Spring level) - Works AFTER DispatcherServlet - Used for business-level checks 💡 Flow: Request → Filter → DispatcherServlet → Interceptor → Controller ⚡ Real use case: - Filter → JWT validation - Interceptor → role-based access 👉 Choosing wrong = messy architecture Know the difference = cleaner backend 🔥 #SpringBoot #Java #BackendDeveloper

Spring Boot Thread Pool Tuning — Hidden performance killer ⚠️ Most developers ignore this… and it hurts performance badly. By default: 👉 Spring Boot uses a limited thread pool If traffic increases: ❌ Requests get queued ❌ Response time increases 💡 Solution: Configure Thread Pool @Bean public TaskExecutor taskExecutor() { ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor(); executor.setCorePoolSize(10); executor.setMaxPoolSize(50); executor.setQueueCapacity(100); executor.initialize(); return executor; } ⚡ Real impact: ✔ Better concurrency ✔ Faster request handling ✔ Stable system under load 👉 Default config is NOT enough for production Performance tuning starts here 🔥 #SpringBoot #Java #Performance

🚀 Spring Boot: More Than Just REST! I recently created this visual to better understand how Spring Boot simplifies application development using powerful features like auto-configuration, dependency injection, and embedded servers. This diagram highlights how different components—Controller, Service, Repository, and Database—work together seamlessly within the Spring ecosystem. Building visuals like this really helps me connect concepts with real-world application flow 💡 📌 Always learning, always improving! #SpringBoot #Java #BackendDevelopment #SoftwareEngineering #LearningJourney #FullStackDeveloper #Tech

Spring Boot @Async — Not as simple as it looks ⚡ Yes, it runs methods asynchronously… But many developers use it WRONG ❌ Example: @Async public void process() { ... } 💡 Behind the scenes: 👉 Runs in a separate thread pool ⚠️ Common mistakes: ❌ Not enabling @EnableAsync ❌ Calling async method internally (won’t work) ❌ Ignoring exception handling 👉 Important: Self-invocation breaks @Async 😱 ✔ Always call from another bean 🔥 Real-world use: - Email sending - Background processing - Non-blocking tasks Async done right = massive performance gain 🚀 #SpringBoot #Java #Async

🔐 Just wrapped up a solid JWT Authentication System using Spring Boot! This project focuses on implementing secure, stateless authentication for REST APIs using JWT and Spring Security. It gave me hands-on experience with how modern applications handle authentication and authorization efficiently If you're looking to understand JWT authentication from basics to advanced level (including best practices and common pitfalls), feel free to check it out: 📖 Full Guide: https://lnkd.in/gBNKjPiM 💻 GitHub Repository: https://lnkd.in/gFkSADPe #Java #SpringBoot #JWT #BackendDevelopment

Have you ever encountered Spring's WebClient throwing a "failed to resolve 'hostname' after x queries" error?. Here's a quick read about the cause and fix. #java #webclient #springboot https://lnkd.in/eq4ntfXz

Spring Security + JWT what happens behind the scenes. Let me break it down in simple words- When you log in: Your username & password go to the server - Spring checks your password using BCrypt (never stores plain text) - if correct, it creates a JWT token and sends it back to you. When you make any request after that: You send that token in every request - Spring reads it, checks the signature, checks if it's expired - if everything is fine, it lets you in - if not, straight up 401 error. The magic part? The server never saves your session anywhere. It just trusts the token it signed. That's why JWT scales so well - no DB hit on every request. Think of it like this: JWT is like a stamp on your hand at a club entrance. You show the stamp - they let you in. No need to check the guest list every time.  3 things Java devs often miss: 1) OncePerRequestFilter - runs your JWT check exactly once per request, no duplicates 2) SecurityContextHolder - this is where Spring stores "who is logged in" for that request thread 3) UserDetailsService - this is your code. Spring calls it, you decide how to load the user. #Java #SpringBoot #JWT #JavaDeveloper

Ever wondered how Spring Boot sets up a DataSource, EntityManagerFactory, and transactions — without you writing a single line of config? That's auto-configuration. And I just wrote my first blog post breaking down exactly how it works. What's covered: → The role of META-INF/spring/AutoConfiguration.imports → @ConditionalOnClass, @ConditionalOnMissingBean, @ConditionalOnProperty → How condition evaluation happens before any bean is created If you've ever typed @SpringBootApplication and moved on without questioning it — this one's for you. This is my first blog, so if I've missed anything or something could be explained better — feel free to drop a comment. Happy to discuss and improve! 🔗 Link in the comments! #SpringBoot #Java #Backend