What is Java?

Java is a class-based, object-oriented programming language designed to have as few implementation dependencies as possible. Created by James Gosling at Sun Microsystems in 1995, Java follows the "write once, run anywhere" principle.

Key Features:

• Platform Independent: Compiles to bytecode that runs on the JVM
• Object-Oriented: Everything is an object (except primitives)
• Strongly Typed: Types are checked at compile time
• Automatic Memory Management: Garbage collection handles memory
• Multi-threaded: Built-in support for concurrent programming

Where Java is Used:

• Enterprise applications
• Android development
• Web backends (Spring, Jakarta EE)
• Big data (Hadoop, Spark)
• Scientific applications

Java Versions: Java follows a 6-month release cycle. LTS versions (8, 11, 17, 21) are recommended for production.

// Every Java program needs a class
public class HelloWorld {
    // Entry point of the program
    public static void main(String[] args) {
        // Print to console
        System.out.println("Hello, World!");
        
        // Variables must declare types
        String name = "Java";
        int version = 21;
        
        System.out.println("Welcome to " + name + " " + version + "!");
        
        // Using printf for formatted output
        System.out.printf("Version: %d%n", version);
    }
}