How to create a REST API with Spring Data REST

Day 3 — Creating Your First Entity & Repository 💬 The Question How do I create my first data model that REST can expose? 🧠 The Explanation Define your Entity → it’s a Java class mapped to a database table. Define your Repository → Spring Data REST will expose it automatically. @Entity public class Category {  @Id @GeneratedValue  private Long id;  private String name;  // getters & setters } @RepositoryRestResource public interface CategoryRepository extends JpaRepository<Category, Long> {} Run the app and open: GET http://localhost:8080/categories You’ll see an empty list (since no categories yet). Add data: curl -X POST -H "Content-Type: application/json" \ -d '{"name":"Electronics"}' http://localhost:8080/categories Learning never stops! Follow me for more Spring Boot, Java, and backend development content — let’s grow together 🙏 #Java #SpringBoot #SpringFramework #BackendDevelopment #SoftwareDevelopment #Programming #RESTAPI #APIDevelopment #BackendEngineer #JavaDeveloper #Developers #TechCommunity #TechLearning #LearnToCode #CareerGrowth

#30DaysOfContainers - Day 2/30 𝐃𝐞𝐩𝐞𝐧𝐝𝐞𝐧𝐜𝐲 𝐇𝐞𝐥𝐥: 𝐖𝐡𝐞𝐧 𝐘𝐨𝐮𝐫 𝐀𝐩𝐩 𝐍𝐞𝐞𝐝𝐬 4 𝐃𝐢𝐟𝐟𝐞𝐫𝐞𝐧𝐭 𝐕𝐞𝐫𝐬𝐢𝐨𝐧𝐬 𝐨𝐟 𝐭𝐡𝐞 𝐒𝐚𝐦𝐞 𝐓𝐡𝐢𝐧𝐠 You start your project fresh. npm install, pip install, mvn clean install — all good. Then after a few months… someone updates a package. Suddenly, half your code breaks 😅 Welcome to Dependency Hell — where one library depends on another version of a library that conflicts with yours. Your backend needs Java 11 Your analytics module was built for Python 3.6 Your old script still runs only on Java 8 And the server has Python 3.10 You get errors that make no sense. You fix one, three more pop up. Welcome, my friend, to the chaos of managing environments. 𝐓𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 𝐖𝐚𝐲: Containers don’t care what’s on your host system. Each container packs its own dependencies, versions, and runtime. You can run: backend: Java 11 analytics: Python 3.6 scripts: Java 8 …all side by side — peacefully No fighting. No “who installed this version?” debates. #Containerization #SoftwareEngineering #DevOps

☀️ Day 12 of My 90 Days Java Challenge – Iterator & Enumerator: The Hidden Navigators of Collections Today was about something that looks simple on the surface — traversing collections. But behind every loop lies a quiet hero — Iterator and its ancestor, Enumerator. Most developers just use for-each and move on. But understanding these two changes the way you think about how data is accessed and controlled. Here’s what I realized 👇 🔹 1️⃣ Enumerator – the old-school traveler Introduced in legacy classes like Vector and Stack, the Enumerator interface came before the Collections Framework. It’s simple — with just hasMoreElements() and nextElement() — but limited. You can only read data, not modify it while traversing. Still, understanding it gives you insight into how Java evolved toward modern iteration. 🔹 2️⃣ Iterator – the modern navigator Iterator replaced Enumerator for a reason — it’s fail-fast, universal, and safe. Methods like hasNext(), next(), and remove() let you traverse and modify collections while keeping data integrity intact. 🔹 3️⃣ Fail-fast behavior isn’t a bug — it’s protection Many don’t realize why ConcurrentModificationException exists. It’s not an error — it’s Java’s way of protecting your collection from inconsistent states during iteration. It teaches a valuable principle: better to fail fast than to corrupt data silently. 🔹 4️⃣ Behind the scenes of “for-each” Even the simple enhanced for-loop (for(String s : list)) uses an Iterator under the hood. It’s a small reminder that abstraction doesn’t replace understanding — it depends on it. 💭 Key takeaway: Iteration isn’t just about looping — it’s about safe navigation through data. Knowing how Enumerator and Iterator work gives you a deeper respect for how Java ensures consistency, even in motion. #Day12 #Java #CoreJava #Collections #Iterator #Enumerator #LearningJourney #90DaysChallenge

𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝘁𝗵𝗲 𝗖𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸! When I first started learning Java, one of the topics that always felt a bit overwhelming was the Collection Framework. So many interfaces, so many classes… I used to wonder — “Where should I even start?” 🤔 That’s when I decided to build my own structured learning path — something I wish existed when I began. And that’s how this repository was born 👇 🔗 Java Collection Framework Repository 👉 https://lnkd.in/gGSN6sU4 💡 Inside this repo, I’ve covered: • 𝗟𝗶𝘀𝘁 𝗜𝗻𝘁𝗲𝗿𝗳𝗮𝗰𝗲 → ArrayList, LinkedList, Vector, Stack • 𝗦𝗲𝘁 𝗜𝗻𝘁𝗲𝗿𝗳𝗮𝗰𝗲 → HashSet, LinkedHashSet, TreeSet • 𝗤𝘂𝗲𝘂𝗲 𝗜𝗻𝘁𝗲𝗿𝗳𝗮𝗰𝗲 → PriorityQueue, Deque, ArrayDeque, LinkedList And of course, the 𝗠𝗮𝗽 𝗜𝗻𝘁𝗲𝗿𝗳𝗮𝗰𝗲, which stands apart from the Collection hierarchy but is equally powerful (HashMap, TreeMap, LinkedHashMap, Hashtable). 🧩 Each concept is explained in a 𝘀𝗶𝗺𝗽𝗹𝗲, 𝗰𝗹𝗲𝗮𝗿, 𝗮𝗻𝗱 𝘀𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗲𝗱 𝘄𝗮𝘆, with 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗮𝗹 𝗲𝘅𝗮𝗺𝗽𝗹𝗲𝘀 that help you not just read but understand and implement. This project is more than just code — it’s my 𝗰𝗼𝗺𝗽𝗹𝗲𝘁𝗲 𝗹𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝗷𝗼𝘂𝗿𝗻𝗲𝘆 through the world of 𝗖𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻𝘀 𝗶𝗻 𝗝𝗮𝘃𝗮 🌱 If you’re someone starting out and want to truly master Collections, I’m sure this repo will be a helpful companion 💪 Let’s keep learning, building, and sharing together! 🚀 #Java #CollectionFramework #LearningJourney #CodingCommunity #GitHub #JavaDeveloper #Programming #LearningInPublic #Developers

🔄 Day 2 – Revision -> Object-Oriented Programming (OOP) Concepts Continuing my Java & Python Full Stack Developer Revision Journey, today’s focus was on one of the most important programming pillars — Object-Oriented Programming (OOP). 💻 Key Concepts Covered: 🟩 Java: Classes, Objects & Constructors Inheritance, Polymorphism, Encapsulation, and Abstraction this and super keywords Method Overloading and Overriding 🐍 Python: Classes & Objects Inheritance and Magic Methods (__init__, __str__) Encapsulation & Composition 🧠 What I Learned Today: OOP makes code more organized, reusable, and scalable. Encapsulation helps protect data — just like real-world boundaries. Inheritance and polymorphism enable code flexibility by reducing duplication. Both Java and Python handle OOP differently, but the core principles remain universal. 💡 Mini Project: I built a small Employee Management System in both Java and Python using OOP principles — defining employee details, calculating bonuses, and demonstrating inheritance (e.g., Manager extending Employee). 📈 This exercise really helped me connect OOP theory to real-world application — something every full stack developer must master before moving to frameworks like Spring Boot or Django. #Day2 #FullStackDeveloper #Java #Python #OOP #LearningJourney #CleanCode #Programming

#DAY63 #100DaysOFCode | Java Full Stack Development #Day63 of my #100DaysOfCode – Java 1. Definition: A Stack in Java is a linear data structure that follows the LIFO (Last In, First Out) principle. This means the last element inserted into the stack is the first one to be removed. It is used when reversing operations, backtracking, undo features, and expression evaluation are needed. 2. Class Information: Package: java.util Class Type: Concrete class Parent Class: Vector<E> Implements: Serializable, Cloneable, Iterable, Collection, List, RandomAccess 3. Introduced Version: Java Version: JDK 1.0 One of the legacy classes in Java (like Vector, Hashtable, Enumeration). 4. Internal Working: The Stack class extends the Vector class, so it inherits all methods from Vector (like add(), remove(), etc.). It adds five specific methods for stack behavior: push(E item) pop() peek() empty() search(Object o) Internally, elements are stored in a dynamic array (inherited from Vector). If capacity is exceeded, the stack automatically grows its size (typically doubles). 5. Key Features: ✅ Follows LIFO order ✅ Synchronized (thread-safe) ✅ Can store null elements ✅ Provides built-in dynamic resizing ✅ Easy to use for simple stack operations A big thanks to my mentor Gurugubelli Vijaya Kumar Sir and the 10000 Coders for constantly guiding me and helping me build a strong foundation in programming concepts. #Java #Coding #Programming #100DaysOfCode #Java #programming #CodeNewbie #LearnToCode #Developer #Tech #ProgrammingTips #JavaDeveloper #CodeDaily #DataStructures #CodingLife

✅ **Java Concept – Encapsulation ☕🔒 **Encapsulation is one of the four pillars of Object-Oriented Programming (OOPs) in Java.** 🔹 **Step 1: Definition** Encapsulation is the process of wrapping data (variables) and code (methods) together into a single unit — usually a class. 💡 Think of it as “data hiding” using private variables and public methods. 🔹 **Step 2: Real-life Example** A bank account — your balance (data) is hidden; you can only access it using deposit() or withdraw() methods. 🔹 **Step 3: Code Example** class Account { private double balance; // data hidden public void deposit(double amount) { balance += amount; } public double getBalance() { return balance; } } 🔹 **Step 4: Logic Flow** • Variables → declared private (cannot access directly). • Methods → declared public (used to modify or fetch values). • Purpose → ensures data security and controlled access. 🔹 **Step 5: Key Benefits** ✅ Improves code maintainability ✅ Protects data from unauthorized access ✅ Easier debugging & modular design #Java #OOPs #Encapsulation #JavaConcepts #LearnJava #CodingBrains #JavaProgramming #ObjectOrientedProgramming #CoreJava #TechLearning #ProgrammingBasics #CodeWithJava #DeveloperCommunity #JavaInterviewPrep #SoftwareEngineering #CodingTips #JavaForBeginners #CleanCode #CodeSmart #TechEducation

🧠 Keep forgetting Java Data Structures concepts? This cheat sheet will help you visualize and remember them easily 💡 📘 Data Structures Cheat Sheet — Part 1 💼 Download the complete Java Cheat Sheets Pack here 👇 🔗 https://lnkd.in/dy44nkaR 🎁 Get all my previous +30 post Design — Free Pack (Leave Comment and Your Rate): 🔗https://lnkd.in/dcnAkS4j ⚡ Part 2 drops next week! Follow me so you don’t miss it 🚀 #LearnEasyWithLaithy #Programming #Java #DataStructures #CheatSheet #BackendDevelopment #SpringBoot #Developers

#DAY54 #100DaysOFCode | Java Full Stack Development #Day54 of my #100DaysOfCode – Java 1. Definition: A Stack in Java is a linear data structure that follows the LIFO (Last In, First Out) principle. This means the last element inserted into the stack is the first one to be removed. It is used when reversing operations, backtracking, undo features, and expression evaluation are needed. 2. Class Information: Package: java.util Class Type: Concrete class Parent Class: Vector<E> Implements: Serializable, Cloneable, Iterable, Collection, List, RandomAccess 3. Introduced Version: Java Version: JDK 1.0 One of the legacy classes in Java (like Vector, Hashtable, Enumeration). 4. Internal Working: The Stack class extends the Vector class, so it inherits all methods from Vector (like add(), remove(), etc.). It adds five specific methods for stack behavior: push(E item) pop() peek() empty() search(Object o) Internally, elements are stored in a dynamic array (inherited from Vector). If capacity is exceeded, the stack automatically grows its size (typically doubles). 5. Key Features: ✅ Follows LIFO order ✅ Synchronized (thread-safe) ✅ Can store null elements ✅ Provides built-in dynamic resizing ✅ Easy to use for simple stack operations A big thanks to my mentor Gurugubelli Vijaya Kumar Sir and the 10000 Coders for constantly guiding me and helping me build a strong foundation in programming concepts. #Java #Coding #Programming #100DaysOfCode #Java #programming #CodeNewbie #LearnToCode #Developer #Tech #ProgrammingTips #JavaDeveloper #CodeDaily #DataStructures #CodingLife