Java Backend Development Fundamentals Day 7 Recap

🚀 Day 55 of #100DaysOfCode — Getting Started with Multithreading in Java Over the past 2 days, I explored one of the most important concepts in Java: Multithreading 🔥 💡 What I Learned 🧵 What is Multithreading? Multithreading allows a program to execute multiple tasks simultaneously, improving performance and efficiency ⚡ 👉 Instead of running tasks one after another, we can run them in parallel. ⚙️ Creating Threads in Java 1️⃣ Using Thread Class Extend the Thread class Override the run() method Start using start() 2️⃣ Using Runnable Interface (Best Practice ✅) Implement Runnable Pass it to a Thread object Start execution using start() 🧠 Key Takeaways ✔ Runnable is preferred over Thread (better design & flexibility) ✔ Supports multiple inheritance ✔ Separates task from execution ✔ Helps in building scalable backend systems ⚠️ Important Concept 👉 Difference between: run() ❌ (normal method call) start() ✅ (creates new thread) 🔥 Real-World Use Cases Backend APIs Payment systems Real-time applications Inventory & billing systems (like the one I'm building 🏪) 🚀 What’s Next? ➡️ Synchronization ➡️ Race Conditions ➡️ ExecutorService (Thread Pool) Learning multithreading feels like unlocking a new level in Java 💪  Huge thanks to my mentor Suresh Bishnoi for simplifying complex concepts like multithreading and pushing me to keep learning consistently. #Java #Multithreading #100DaysOfCode #BackendDevelopment #LearningJourney

Day 56-What I Learned In a Day (JAVA) Today I learned an important concept in Java - how to access non-static members, both within the same class and across different classes, along with the concept of code reusability. Accessing Non-Static Members within the Same Class Non-static members belong to an object, so they can be accessed directly inside non-static methods. Key point: No object creation is needed when accessing inside the same class’s non-static method. Accessing Non-Static Members from Another Class To access non-static members from a different class, we must create an object of that class. Example: ClassName obj = new ClassName(); obj.methodName(); This allows us to call methods and use variables defined in another class. Code Reusability One of the biggest advantages I understood today is code reusability. Instead of writing the same logic again: • We create a method once • Reuse it in multiple classes using objects This reduces: • Code duplication • Errors • Development time #Java #OOP #CodeReusability #Programming #LearningJourney #DeveloperLife

Here are three golden rules that make a constructor different from a regular method. First, it must have the same name as the class. Second, it has no return type — not even void. Third, it runs automatically when you use the new keyword. And here is a bonus fact that surprises most beginners — if you never write a constructor in your class, Java silently creates a default one for you in the background. Pretty cool, right? Swipe through the image below to see exactly how constructors look in real code 👇 #Java #JavaProgramming #JavaDeveloper #OOP #ObjectOrientedProgramming

Many developers start Spring Boot too early. Then struggle… Not because Spring is hard but because the Java foundation is shaky. So I wrote something I wish I had when starting: A clear roadmap of what to learn in Java before Spring Boot. From syntax → OOP → collections → streams → debugging Plus a realistic timeline for when you're actually ready. No guessing. No rushing. Just solid foundations. If you're learning Java, this one is for you. 📖 Read here: https://lnkd.in/d7xnuwP5 What would you add to this roadmap? #Java #JavaRoadMap

Spring Framework has a steep learning curve. It doesn't have to. Most tutorials throw you into annotations and config files before explaining what's actually happening. That's why beginners get lost. I wrote a complete, beginner-focused guide that explains Spring the right way — starting with the problem each concept solves. ✅ IoC & Dependency Injection ✅ Beans, scopes, and the container ✅ XML, Java, and Annotation configuration ✅ Auto-wiring and resolving ambiguity ✅ Spring Boot demystified By the end, you won't just know how to use Spring. You'll understand why it works the way it does. That's the difference between memorising and actually knowing. 👉 Link - https://lnkd.in/gSPqnJ8u #Java #SpringBoot #SpringFramework #SoftwareEngineering #BackendDevelopment #JavaDeveloper

🚀 Exploring VS Code Extensions – Built a Practical Java Utility While working on improving my development workflow, I created a custom VS Code extension that reduces repetitive coding in Java. 👉 Instead of manually writing classes, you can simply write: abc.print("Hello"); And the extension automatically generates the required Java class in real-time. 💡 Key Capabilities: Detects any .print() usage Dynamically creates the corresponding class Works instantly while editing Java files Helps reduce boilerplate code ⚙️ Tech Stack: TypeScript • VS Code Extension API • Java 📦 How to Use (Important): Since this is not published on the VS Code Marketplace, you can use it locally: Download the .vsix file from GitHub Open VS Code Press Ctrl + Shift + P Select Install from VSIX Choose the downloaded file Start using it in any .java file 🔗 GitHub Repository: (https://lnkd.in/dnj575B3) I’m continuously working on improving this and adding more features. Feedback and suggestions are always welcome! #Java #VSCode #DeveloperTools #TypeScript #Coding #SoftwareDevelopment #BuildInPublic

🚀 Day 1 of My Java Journey Today I started learning Java, focusing on understanding the fundamentals that are directly useful in real-world development. Here’s a quick summary of what I worked on: ▪ Annotations and how they influence application behavior ▪ Retention policies and how long annotations remain available ▪ Using @RestController to build REST APIs in a simpler way ▪ The role of controllers in handling HTTP requests and responses ▪ Why using objects instead of strings leads to cleaner and more scalable code ▪ The limitation of in-memory storage for long-term data handling ▪ Using tools like RoboPOJO to quickly generate Java classes My goal is to keep things practical—focusing on writing clean code and understanding how things work behind the scenes. Looking forward to building more and improving consistently. https://lnkd.in/gBDrQuyC #Java #SpringBoot #BackendDevelopment #SoftwareEngineering #CodingJourney #LearningInPublic #Tech #Developers #APIs

🚀 Recently, I revisited a Java & Spring Boot course I had started earlier — this time with a focus on going beyond day-to-day development. 💡 While working on projects, we often use frameworks efficiently, but this helped me explore what happens under the hood. 📌 Some key concepts I deep-dived into: • ⚙️ How Spring Boot auto-configuration actually works • 🔄 Bean lifecycle & dependency injection at a deeper level • 🔁 Writing idempotent APIs and handling retries • 🧩 Understanding transaction propagation in real scenarios • 🏗️ Basics of system design for scalable backend services • 🧵 Thread safety and concurrency basics in Java 🔍 What made this valuable is connecting these concepts with real production scenarios and improving how I think about backend systems. 📈 Continuous improvement > Comfort zone. #Java #SpringBoot #BackendDevelopment #Microservices #SystemDesign #Learning

Understanding the difference between @Qualifier and @Primary is key when working with multiple beans in Spring. This visual guide clearly explains: 👉 How Spring resolves bean conflicts 👉 When to use @Qualifier for precise control 👉 When to use @Primary as a default bean 👉 Real-world example with multiple implementations 👉 Best practices to avoid confusion in dependency injection Key takeaway: • Use @Primary when one bean should be the default • Use @Qualifier when specific control is needed A simple concept, but very important for writing clean and maintainable Spring Boot applications. Useful for: ✔ Java developers ✔ Spring Boot learners ✔ Interview preparation Feel free to check it out and share your thoughts 🙌 #SpringBoot #SpringFramework #Java #BackendDevelopment #DependencyInjection #Developers #Coding

🚀 Day 1 – Strengthening Java Fundamentals Starting with something simple but powerful: How Java Works Behind the Scenes When we write a Java program, it doesn’t directly run on the machine. Instead: 👉 Java code → compiled into Bytecode 👉 Bytecode → executed by the JVM (Java Virtual Machine) Why this matters? Because this is what makes Java platform independent — “Write Once, Run Anywhere.” Also, JVM doesn’t just run code — it handles: ✔ Memory Management (Garbage Collection) ✔ Security ✔ Performance optimization Understanding this foundation helps in writing better, optimized applications—especially when working with frameworks like Spring Boot. #Java #BackendDevelopment #LearningInPublic #JVM #SoftwareEngineering