Java — Introduction

What is Java?

Java is one of the most used programming languages in the world. It runs on billions of devices — Android phones, bank systems, enterprise servers, Minecraft.

Its motto: "write once, run anywhere." Java code compiles to bytecode that any device with a Java runtime can execute, whether Windows, Mac or Linux.

What Java looks like

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

Yes — printing one line needs all of that ceremony. Java believes in structure: everything lives inside a class, and execution starts at main.

It feels heavy at first, but that same structure keeps huge codebases organized — which is why big companies love it.

Why learn Java?

Massive job market (enterprise backends, Android)
Strong typing catches mistakes before running
Enormous ecosystem of libraries
Skills transfer well to C#, C++ and Kotlin

Getting started

Install the JDK from adoptium.net, then compile and run:

javac Main.java   → produces Main.class
java Main         → prints Hello, world!

Next lesson: we break down what every piece of that hello-world actually means.

Frequently Asked Questions about Introduction

What is Introduction in Java?

Introduction is a fundamental concept in Java. This lesson explains it step by step with clear examples, making it easy for beginners to understand.

How do I learn Introduction?

Start by reading the explanation above, then try the code examples. Practice by modifying the examples and experimenting with different values. Hands-on practice is the best way to learn Introduction.

Why is Introduction important in Java?

Introduction is essential for Java development. Understanding this concept will help you write better code and solve real-world problems more effectively.