Java Getting Started

Java Install

Some PCs might have Java already installed.

To check if you have Java installed on a Windows PC, search in the start bar for Java or type the following in Command Prompt (cmd.exe):

If Java is installed, you will see something like this (depending on version):

If you do not have Java installed on your computer, you can download it for free at oracle.com.

Note: In this tutorial, we will write Java code in a text editor. However, it is possible to write Java in an Integrated Development Environment, such as IntelliJ IDEA, Netbeans or Eclipse, which are particularly useful when managing larger collections of Java files.

Java Quickstart

In Java, every application begins with a class name, and that class must match the filename.

Let's create our first Java file, called Main.java, which can be done in any text editor (like Notepad).

The file should contain a "Hello World" message, which is written with the following code:

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

Save the code in Notepad as "Main.java". Open Command Prompt (cmd.exe), navigate to the directory where you saved your file, and type "javac Main.java":

This will compile your code. If there are no errors in the code, the command prompt will take you to the next line. Now, type "java Main" to run the file:

The output should read:

Congratulations! You have written and executed your first Java program.

W3Schools' Java Editor

When learning Java at W3Schools.com, you can use our "Try it Yourself" tool, which shows both the code and the result. It is used to write, run, and test code right in your browser:

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