• We need to write the file name the same as the class name.
• By convention, class names begin with a capital letter and capitalize the first letter of each word they include (e.g., SampleClassName ).

public class Main {
  public static void main(String[] args) 

	//main() is called a method, it is the main method of the program. 
	//we use public so that the main method can be accessible in the whole program.
	//void is used for no return type.
	//we use static so that we can work in it without creating an object for it.
	
	{
    System.out.println("Hello World");//System is a class
  }
}

• Every line of code that runs in Java must be inside a class.

• Java is case-sensitive.

• Boilerplate code - The code which we get as default skeleton

• Every program must contain the main() method. Any code inside the main() method will be executed.

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

  • The curly braces {} mark the beginning and the end of a block of code.
  • System is a built-in Java class that contains useful members,
    • such as out, which is short for "output".
    • The println() method, is short for "print line". (each println() will add a new line.)

• NOTE

  In Java, the String[] args is used to pass command-line arguments to the main method of a program. When you run a Java program from the command line, you can provide additional information (arguments) that can be accessed by the program during its execution.

  Here's a brief explanation:

  • String: It indicates that the command-line arguments are an array of strings.
  • args: This is just a variable name; you could use any valid identifier. It stands for "arguments."

• There is also a print() method, which is similar to println().

  • The only difference is that it does not insert a new line at the end of the output.
  • So, it works like we are writing in the same line.

• Every line must end with the semicolon “ ; “.

• NOTE

  • String and System are written with capital “ S “.