HackForge Academy’s Post

Spring Boot field validation ensures incoming request  data is correct before processing. It helps  prevent invalid input such as empty fields,  wrong email format, or short passwords.. . . . . . . . . . #Java #JavaProgramming #JavaDeveloper #JavaCode #JavaScript #JavaCommunity #JavaTutorial #JavaLearning #JavaDevelopment #JavaLife #JavaLovers #JavaProjects #JavaCoding #JavaTips #JavaFramework #Java8 #JavaEE #JavaForBeginners #JavaGeek #JavaWorld #hackforge

#Java #JPA Tip: by default lazy loading in #Hibernate works only for relationships, not for basic attributes. In order to make it work you have to use bytecode enhancement through a plugin. Then fields marked as lazy will be loaded when they are first accessed.

Built DTOForge, a small Spring Boot tool that generates Java DTOs from JSON. Useful when integrating external APIs and you do not want to keep writing DTOs by hand. Supports: * Java records * Java classes * nested objects * arrays * optional Jackson annotations Source: `https://lnkd.in/eWEpUxPY Medium article: https://lnkd.in/eDmK-eVx #Java #SpringBoot #OpenSource #BackendDevelopment #APIIntegration

Cron is a time-based scheduler used to  execute tasks automatically at specific intervals such  as every minute, daily at 9 AM,  or every Monday. In Spring Boot, cron  jobs are implemented using the @Scheduled annotation.. . . . . . . . . . #Java #JavaProgramming #JavaDeveloper #JavaCode #JavaScript #JavaCommunity #JavaTutorial #JavaLearning #JavaDevelopment #JavaLife #JavaLovers #JavaProjects #JavaCoding #JavaTips #JavaFramework #Java8 #JavaEE #JavaForBeginners #JavaGeek #JavaWorld #hackforge

🚀 Runnable vs Callable in Java Concurrency — Quick Notes Both Runnable and Callable are Functional Interfaces ✅ 👉 That means you can use Lambda Expressions with them (Java 8+) 🔹 Runnable (Java 1.0) * Functional Interface ✔️ * Method: run() * Return Type: ❌ No return value * Exception Handling: ❌ Cannot throw checked exceptions * Use Case: Fire-and-forget background tasks 🔹 Callable (Java 5.0) * Functional Interface ✔️ * Method: call() * Return Type: ✅ Returns result (Future<V>) * Exception Handling: ✅ Can throw checked exceptions * Use Case: Tasks that need results or error handling 💡 Key Difference * Use Runnable when you don’t care about the result * Use Callable when you need a result or better exception handling ⚡ Lambda Example Runnable r = () -> System.out.println("Running task"); Callable<Integer> c = () -> 10 + 20; 🔥 In modern Java (Java 8+ to Java 21 Virtual Threads), functional style + concurrency = clean & scalable code. #Java #Concurrency #Multithreading #FunctionalProgramming #JavaDeveloper #InterviewPrep

@ControllerAdvice is a Spring Boot annotation used  for global exception handling across the entire  application. Instead of writing error-handling logic inside  every controller, it centralizes the logic in  one place.. . . . . . . . . . #Java #JavaProgramming #JavaDeveloper #JavaCode #JavaScript #JavaCommunity #JavaTutorial #JavaLearning #JavaDevelopment #JavaLife #JavaLovers #JavaProjects #JavaCoding #JavaTips #JavaFramework #Java8 #JavaEE #JavaForBeginners #JavaGeek #JavaWorld #hackforge

@ControllerAdvice is a Spring Boot annotation used  for global exception handling across the entire  application. Instead of writing error-handling logic inside  every controller, it centralizes the logic in  one place.. . . . . . . . . . #Java #JavaProgramming #JavaDeveloper #JavaCode #JavaScript #JavaCommunity #JavaTutorial #JavaLearning #JavaDevelopment #JavaLife #JavaLovers #JavaProjects #JavaCoding #JavaTips #JavaFramework #Java8 #JavaEE #JavaForBeginners #JavaGeek #JavaWorld #hackforge

🚀 Constructor References (Java) A constructor reference refers to the constructor of a class. The syntax is `ClassName::new`. This is useful when you need to create new objects within a lambda expression. Constructor references simplify the process of object creation when a functional interface expects a supplier of objects. #Java #JavaDev #OOP #Backend #professional #career #development

#Java Why does Java not provide default value to local variables? 👉 Answer Java does not give default values to local variables to avoid using uninitialized (garbage) data and ensure safety. 📌 Example class Test { public static void main(String[] args) { int x; System.out.println(x); // ❌ Compile-time error } } ✔ Error: variable x might not have been initialized 📏 Rules (Simple Points) 🔒 Local variables must be initialized before use ❌ No default value is assigned by Java ⚠ Compiler checks this at compile time 📦 Instance & static variables get default values, but local variables do not 🎯 Summary 👉 Java forces initialization to prevent bugs and ensure clean code

Today while revising Core Java, I came across a small but interesting concept Anonymous Object ✅ class AnonymousObject { public void AnonymousObj() { System.out.println("Anonymous object practice"); } AnonymousObject() { System.out.println("In constructor"); } } public class Main { public static void main(String[] args) { new AnonymousObject().AnonymousObj(); new AnonymousObject().AnonymousObj(); } } Every time new AnonymousObject() is used, a new object is created and the constructor gets called. Simple concept, but clarity matters. 😊 #Java #CoreJava #Learning