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Basic Structure of a Java Program: Understanding our First Java Hello World Program

Basic Structure of a Java Program

package com.company; // Groups classes
public class Main{	// Entrypoint into the application
	public static void main(String[]args){
		System.out.println(“Hello World”);
	}
}

Working of the "Hello World" program shown above :

1. package com.company :

   • Packages are used to group the related classes.
   • The "Package" keyword is used to create packages in Java.
   • Here, com.company is the name of our package.

2. public class Main :

   • In Java, every program must contain a class.
   • The filename and name of the class should be the same.
   • Here, we've created a class named "Main".
   • It is the entry point to the application.

3. public static void main(String[]args){..} :

   • This is the main() method of our Java program.
   • Every Java program must contain the main() method.

4. System.out.println("Hello World"):

   • The above code is used to display the output on the screen.
   • Anything passed inside the inverted commas is printed on the screen as plain text.

Naming Conventions

• For classes, we use Pascal Convention. The first and Subsequent characters from a word are capital letters (uppercase).
  Example: Main, MyScanner, MyEmployee, CodeWithHarry

• For functions and variables, we use camelCaseConvention. Here the first character is lowercase, and the subsequent characters are uppercase like myScanner, myMarks, CodeWithHarry