Java Variables A variable in Java is a container that holds data during program execution. Each variable has a name, data type, and value . 1. Declaration and Initialization Before a variable can be used, it must be declared, which involves specifying its data type and a unique name. int age = 25; // declaration + initialization String name = "Test"; double salary; // only declaration salary = 500.50; // initialization later 2. Types of Variables Local Variable → Variables declared inside a method/block/constructor. Instance Variable → Variables declared inside a class but outside methods (object-specific). Static Variable → Variables declared with static , shared across all objects. class Employee { String name; // instance variable static String company = "XYZ Ltd"; // static variable voi...
I have created a detailed roadmap that takes you from beginner Core Java to advanced Java concepts. I’ve broken it down into 4 phases to help you keep track of your progress. You will learn important concepts and tools during each phase. Java Basics: Tutorials on getting started with Core Java. Advanced Java Concepts: Dive into topics like concurrency, memory management, and JVM internals, web components. Java Frameworks: Popular frameworks like Spring, Hibernate. Java for Web Development: Focus on using Java for building web applications. Java Best Practices: Code optimization, clean code, and design patterns. Phase 1 : Java Fundamental (Beginner Level) 1. Introduction to Java Install Java (JDK) and set up your IDE (e.g., IntelliJ IDEA, Eclipse, VS Code). Hello World Program : Start by writing and running the simplest Java program. Understand the Java Development Environment : Learn how JVM and JRE work . 2. Core Syntax & Basics Constructs Variables and Data Types : int ...