Hello World!

Part of the Fundamentals section of Coddy's Java journey — lesson 2 of 73.

The "Hello World!" is a simple program that outputs Hello World! to the screen.

In Java, we use System.out.println() to print output to the console. The text to be printed is placed within double quotes and enclosed in parentheses.

Note that System is capitalized — Java is case-sensitive, so system.out.println() will not work.

Let's take a look at the "Hello World!" program in Java:

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

Here is what each part does:

public class Main — defines a class named Main. Every Java program must have at least one class.
public static void main(String[] args) — this is the main method, the entry point of every Java program. When you run a Java program, execution always starts here.
System.out.println("Hello World!") — prints the text inside the quotes to the console, followed by a new line.

Challenge

Beginner

Use the code view to write a program that outputs Hello World!

Note that anything inside quotation marks is case sensitive. For example:
System.out.println("Hello World!");
System.out.println("hello world!");
are different things (notice the capital letters in the first line).

Try it yourself

public class Main {
    public static void main(String[] args) {
        // Write your code below
        
        
    }
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

JavaHello World!Comments Basic Program Structure

4Operators Part 1

Arithmetic Operators Modulo Operator Increment/Decrement Post Increment/Decrement Arithmetic Shortcuts Comparison Operators String Comparison

7Basic IO

System.out Methods Formatting Output Scanner Class Recap - Till 120 Recap - True or False

10Methods (Functions)

Declaring Methods Method Parameters Return Types Method Overloading Recap - Sigma Function Recap - Validation Function Void Methods

13String Operations

String Methods Part 1 String Methods Part 2 String Formatting String Comparison

2Variables Part 1

Numbers String Boolean char Type Declaration

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Logical Operators Part 4

8Calculator App

Welcome Message Getting Numbers

Basic Operations

Formatted Output

11Arrays Basics

Declaring Arrays Accessing Elements Modifying Arrays Array Methods Recap - Product Array Recap - Reversed Array

14Final Challenges

Number Pattern Pattern Finder Student Grade Calculator

3Variables Part 2

Constants Naming Conventions Recap - Initialize Variables Type Casting Part 1 Type Casting Part 2

6Decision Making

If Statement If - Else Switch Statement Ternary Operator Recap - If Else Nested If - Else

9Loops

For Loop Part 1 While Loop Do While Loop Break Continue For Loop Part 2 Nested Loop Infinite Loop Recap - Dynamic Input

12Iterating Over Arrays

Using For Loop Enhanced For Loop Common Array Operations