Java Command Line Arguments

In Java, command line arguments provide a way to pass information to a Java application when it is run. This guide will explore the syntax, usage, and considerations for handling command line arguments in Java.

Syntax

To access command line arguments in a Java program, you use the args parameter in the main method:

public class CommandLineArgumentsExample {
    public static void main(String[] args) {
        // Code to handle command line arguments
    }
}

Example

Let's consider an example where we print and use command line arguments:

public class CommandLineArgumentsExample {
    public static void main(String[] args) {
        System.out.println("Number of command line arguments: " + args.length);

        for (int i = 0; i < args.length; i++) {
            System.out.println("Argument " + (i + 1) + ": " + args[i]);
        }
    }
}

Output

The output will display the number and values of command line arguments when the program is executed:

Number of command line arguments: 3
Argument 1: arg1
Argument 2: arg2
Argument 3: arg3

Explanation

• The args array in the main method contains the command line arguments passed when the Java program is executed.
• The length of the args array gives the number of command line arguments.
• The program then iterates through the array to print each command line argument.

Use

Command line arguments are useful when:

• You want to provide input to your Java program when running it from the command line.
• Customizing the behavior of the program without modifying the source code.
• Automating tasks by passing parameters to a Java application.

Important Points

• Command line arguments are passed as strings, and it's the responsibility of the program to parse them into appropriate data types.
• The order of command line arguments matters; the first argument is args[0], the second is args[1], and so on.
• Java automatically splits command line arguments based on whitespace.

Summary

Java command line arguments allow you to pass information to your Java application at runtime. By using the args parameter in the main method, you can access and process these arguments. This feature enhances the flexibility and usability of your Java programs, enabling them to be more versatile and adaptable to different scenarios.