Java Syntax

Java Syntax

Every Java program is made of classes, and inside the classes you write statements that tell the computer what to do.

A minimal program

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

Breaking it down

• public class Main declares a class named Main. A class is a container for code.
• public static void main(String[] args) is the entry point where the program starts.
• System.out.println("Hello World") prints text to the screen.
• Every statement ends with a semicolon ;.

The main method

The main method must be written exactly like this or the program will not run:

public static void main(String[] args) {
  // your code here
}

Curly braces

Curly braces { } mark the beginning and end of a block of code, such as a class or a method.

Case sensitivity

Java is case sensitive. System, system, and SYSTEM are three different names. Always match the exact spelling of keywords and method names.

TL;DR

• A Java program starts with a class and the main method.
• Statements end with a semicolon.
• System.out.println() prints text.
• Curly braces group blocks of code.