Explanation of "Hello, World!"

Java “Hello, World!” Program link

Code Example link

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

Explanation link

1. Class Definition

     public class HelloWorld {
     

   • public: An access modifier that makes the class accessible from any other class.
   • class: A keyword used to define a class in Java.
   • HelloWorld: The name of the class. It must match the file name (HelloWorld.java).

2. Main Method

     public static void main(String[] args) {
     

   • public: An access modifier that makes the method accessible from any other class.
   • static: A keyword that allows the method to be called without creating an instance of the class.
   • void: The return type of the method, indicating it does not return any value.
   • main: The name of the method. It is the entry point of the program.
   • String[] args: The parameter of the main method. It is an array of String objects that can store command-line arguments.

3. Print Statement

     System.out.println("Hello, World!");
     

   • System: A built-in class that contains several useful methods and fields, including out.
   • out: A static member of the System class, which is an instance of PrintStream. It is connected to the console.
   • println: A method of PrintStream that prints the argument passed to it, followed by a new line.

Steps to Run the Program link

1. Write the Code

   • Create a file named HelloWorld.java and write the code shown above.

2. Compile the Code

   • Open a terminal or command prompt.
   • Navigate to the directory where the file is saved.
   • Run the command:

     javac HelloWorld.java
     

   • This will compile the Java file and create a HelloWorld.class file.

3. Run the Program

   • In the same terminal or command prompt, run the command:

     java HelloWorld
     

   • This will execute the compiled bytecode and print Hello, World! to the console.