CodeInvestigator’s Post

Quick Spring Boot tip that saves debugging time: If your @Scheduled method isn't running, check two things: 1. Is @EnableScheduling on your main class? 2. Is the method public and inside a Spring-managed bean? Common mistake: @Component public class JobRunner {   @Scheduled(fixedRate = 5000)   private void runJob() {     // won't run   } } The method is private. Spring can't proxy it. Fix: @Scheduled(fixedRate = 5000) public void runJob() {   // works } Small detail. Easy to miss. Costs 30 minutes of "why isn't this working?" #SpringBoot #Java #BackendDevelopment #Programming

📘 Spring Notes – 4 Understanding Dependency Injection is one thing… Implementing it is where the real learning happens 💻 Today I worked on: ✔️ Setter vs Constructor Injection ✔️ Autowiring ✔️ Spring Bean Configuration (XML) Also pushed my practice code to GitHub: 👉 https://lnkd.in/gN-j5n3V Slowly building strong backend fundamentals 🚀 Follow for daily updates on my Spring journey. #Java #SpringBoot #Backend #Developers #Learning #TechJourney

Stop wrestling with boilerplate code! 🛠️ I just launched Part 1 of my new series on Spring Boot 4 and Java 17. In this video, I break down the "magic" behind Spring Boot and show you how to go from zero to a production-ready REST API in minutes. What we cover: ✅ Initializing a project with Spring Initializr ✅ Understanding the Spring Boot architecture ✅ Setting up your first REST Controller ✅ Integrating Swagger UI (OpenAPI) for instant documentation If you're looking to modernize your backend stack or just starting out with Java, this guide is for you. 📺 Watch the full tutorial here: https://lnkd.in/dJGRH3z2 Are you currently using Spring Boot 2 or have you already made the jump to 3+? Let’s discuss in the comments! 👇 #SpringBoot #Java17 #BackendDevelopment #SoftwareEngineering #SwaggerUI #MathebulaAcademy #CodingLife #SouthAfricaTech

Everything you need to know about Spring Security in one place! From SecurityFilterChain to JWT vs Session — this cheat sheet covers it all. Bookmark this before your next Spring Boot project #springsecurity #SpringSecurity #SpringBoo #Java #JWT #WebSecurity #BackendDevelopment #JavaDeveloper #Programming #SoftwareEngineering #REST #APIDesign #TechTips #Developer

Spent 10 minutes wondering why my Spring Boot bean wasn't being injected. No errors. No warnings. Just null. The code looked fine: @Service public class PaymentService { // logic } But Spring couldn't find it. The problem: My main class was in com.myapp My service was in com.payments Spring Boot only scans the package where @SpringBootApplication lives and its sub-packages. The fix: Move the service under com.myapp.payments Or add: @SpringBootApplication(scanBasePackages = "com") But be careful with broad scans - they slow startup. Simple rule: Keep everything under your main package. #SpringBoot #Java #BackendDevelopment #Programming

Spent 15 minutes wondering why my @Value annotation wasn't injecting the property. The code: @Component public class AppConfig {   @Value("${app . name}")   private String appName;   public AppConfig() {     System.out.println(appName);   } } It printed null every time. The problem: @Value injection happens after the constructor runs. In the constructor, Spring hasn't injected anything yet. The fix: Use @PostConstruct instead: @PostConstruct public void init() {   System.out.println(appName); } Or use constructor injection: public AppConfig(@Value("${app . name}") String appName) {   this.appName = appName; } Constructor runs first. Injection happens after. Simple timing issue. Easy to miss. #SpringBoot #Java #BackendDevelopment #Programming

📘 Spring Boot Annotations Cheat Sheet Sharing a quick reference PDF covering important Spring Boot annotations used in real-world backend development. This includes: ✅ Core annotations ✅ REST API annotations ✅ Dependency Injection ✅ Configuration annotations ✅ Commonly used annotations in projects Perfect for quick revision & interview preparation 🚀 #SpringBoot #Java #BackendDevelopment #JavaDeveloper #Programming #InterviewPreparation

Dependency Injection is one of those concepts that sounds more complicated than it really is. At its core, it simply means: Instead of a class creating its own dependencies, you give those dependencies to it from the outside. Why does that matter? Because it makes the code: • easier to test • easier to maintain • less tightly coupled • clearer about what it actually needs #SoftwareEngineering #Java #SpringBoot #BackendDevelopment #CleanCode #DependencyInjection #Programming

⚔️ Spring vs Spring Boot Spring Framework 🔹 Requires manual configuration 🔹 More control and flexibility 🔹 Takes more setup time Spring Boot 🔹 Auto-configuration (less setup) 🔹 Embedded server (no need to deploy separately) 🔹 Faster development 💡 In short: Spring Boot is built on top of Spring to make development quicker and easier. 👉 Use Spring Boot for rapid development 👉 Use Spring when you need full control #Java #SpringFramework #SpringBoot #BackendDevelopment #Coding