// Java Program to Illustrate First ArgumentclassGFG{publicstaticvoidmain(String[]args){// Printing the first argumentSystem.out.println(args[0]);}}

Output:

Explanation:

• Running java GFG GeeksForGeeks prints GeeksForGeeks because the argument is passed to main(String[] args).
• If no arguments are given (e.g., java GFG), it throws ArrayIndexOutOfBoundsException since args is empty.

Why Use Command Line Arguments?

• It is used because it allows us to provide input at runtime without modifying the whole program.
• It helps to run programs automatically by giving them the needed information from outside.

Working of Command-Line Arguments

• Command-line arguments in Java are space-separated values passed to the main(String[] args) method.
• JVM wraps them into the args[] array, where each value is stored as a string (e.g., args[0], args[1], etc.).
• The number of arguments can be checked using args.length.

Example: Display Command-Line Arguments Passed to a Java Program

To compile and run a Java program in the command prompt, follow the steps written below.

• Save the program as Hello.java
• Open the command prompt window and compile the program- javac Hello.java
• After a successful compilation of the program, run the following command by writing the arguments- java Hello
• For example - java Hello Geeks at GeeksforGeeks
• Press Enter and you will get the desired output.

classGeeks{// Main driver methodpublicstaticvoidmain(String[]args){// Checking if length of args array is// greater than 0if(args.length>0){// Print statementsSystem.out.println("The command line"+" arguments are:");// Iterating the args array// using for each loopfor(Stringval:args)System.out.println(val);}elseSystem.out.println("No command line "+"arguments found.");}}

Output: