Java Syntax

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

Every line of code that runs in Java must be inside a class. The classname should always start with an uppercase first letter.

In our example, we named the class Main.

Note: Java is case-sensitive. MyClass and myclass would be treated as two completely different names.

The name of the Java file must match the class name. So if your class is called Main, the file must be saved as Main.java. This is because Java uses the class name to find and run your code. If the names don't match, Java will give an error and the program will not run.

When saving the file, save it using the class name and add .java to the end of the filename

The main Method

The main() method is required in every Java program. It is where the program starts running:

public static void main(String[] args)

Any code placed inside the main() method will be executed.

main() is the starting point of every Java program.

System.out.println()

Inside the main() method, we can use the println() method to print a line of text to the screen:

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

Note: The curly braces {} mark the beginning and the end of a block of code.

System.out.println() may look long, but you can think of it as a single command that means: "Send this text to the screen."

Here's what each part means):

System is a built-in Java class.

• out is a member of System, short for "output".
• println() is a method, short for "print line".

Finally, remember that each Java statement must end with a semicolon (;).