*☕ Core Java Fundamentals – Quick Refresher (Must-Know for Every Java Developer)* ✅ 📌 *1. Data Types & Variables* - int, float, double, boolean, char, long - Declare and initialize variables - Type casting (implicit & explicit) 📌 *2. Operators* - Arithmetic: + - * / % - Relational: > < >= <= == != - Logical: && || ! - Assignment: = += -= *= 📌 *3. Control Flow* - if, else-if, switch - Loops: for, while, do-while - break & continue usage 📌 *4. Arrays & Strings* - 1D & 2D arrays - String methods: length(), charAt(), substring(), equals(), split(), etc. - StringBuilder for efficient string manipulation 📌 *5. OOP Concepts (Pillars of Java)* - Class & Object - Inheritance (extends) - Polymorphism (overloading/overriding) - Abstraction (abstract class, interface) - Encapsulation (private fields + getters/setters) 📌 *6. Exception Handling* - try-catch-finally - Multiple catch blocks - throw vs throws - Custom exception class *💡 Bonus Tip:* Master these before jumping into frameworks like Spring or tools like Hibernate. *React ❤️ for more!*