Java

Java Basics

Java Variables & Data Types

Java Control Flow

Java Arrays

Java Methods

Java Classes & Objects

OOP Principles

Java Utilities

Error Handling

Collections Framework

Java File Handling

Advanced Java

Java Practical How-To's

Java Introduction

🔹 What is Java?

Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It was developed by James Gosling at Sun Microsystems and released in 1995.

Java programs are compiled into bytecode and run on the Java Virtual Machine (JVM), making them platform-independent.

🔹 Why Learn Java?

Write once, run anywhere (WORA) — platform-independent
Object-Oriented Programming (OOP) support
Large standard library
Used in Android development, web apps, enterprise software, etc.
Strong memory management and security features

🔹 Features of Java

Platform Independent
Object-Oriented
Simple and Secure
High Performance
Multithreaded
Portable and Robust

🔹 Java Program Structure

public class Main {
  public static void main(String[] args) {
    System.out.println("Hello, World!");
  }
}

🔸 Explanation:

class Main — defines the class
main() — entry point of Java programs
System.out.println() — prints output

🔹 How to Run Java Code

Write the code in a file named Main.java
Compile using:
```
javac Main.java
```
Run using:
```
java Main
```

Practice Questions

Q1. Print "Hello Java"

Q2. Add two integers

Q3. Use single-line comment

Q4. Take user input using Scanner

Q5. Multiply two floating-point numbers