What are Command-Line Arguments in Java?

[Beter 2 Burn Out]

Hi friends,
I have recently started working with the Core Java. Now I am working with the basic classes that are used in Java. I want to know how command line arguments are passed in Java.? Since, you have solved my issues many times I thought that posting here would be helpful. Please tell me what are Command-Line Arguments in Java.?? Any other information would be grateful.!!

[Allan.d]

You can put any number of arguments in your Java application because, your Java application can accept any number of arguments from the command line. Command-line arguments allow the user to affect the operation of an application. It is not necessary for the operating system to also pass a parameter specifying the number of arguments. The user can enter command-line arguments when invoking the application. When running the java program from java command, the arguments are provided after the name of the class separated by space. You will come to know more about this while doing the coding.

[Warner]

You will have to enter the command-line arguments when invoking the application. Lets take an example so that it would be useful for you to understand the concepts. Suppose a Java application called Align sorts lines in a file. To sort the data in a file named people.txt, a user would enter:

java Align people.txt

When an application is launched, the runtime system passes the command-line arguments to the application's main method via an array of Strings.

[Praetor]

You are not having an idea of how to pass the command line arguments, so I thought that giving an demonstration would help you. The following example explains the same :

public class CmdArgsDemo{
    public static void main(String[] args){
        System.out.println("The following command line arguments were passed:");
        
        for (int i=0; i < args.length; i++){
            System.out.println("arg[" + i + "]: " + args[i]);
        }
    }
}

[kelfro]

The user enters command-line arguments when invoking the application and specifies them after the name of the class to be run. The Java syntax for command-line arguments is as follows :

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

Hope that this post would have helped you.

[opaper]

The Echo example displays each of its command-line arguments on a line by itself :

public class ExampleEcho {
    public static void main (String[] args) {
        for (String s: args) {
            System.out.println(s);
        }
    }
}

[Reegan]

If an application needs to support a numeric command-line argument, it must convert a String argument that represents a number. So i have provided you with a code snippet that converts a command-line argument to an int :

int oneArg;
if (args.length > 0) {
    try {
        oneArg = Integer.parseInt(args[0]);
    } catch (NumberFormatException e) {
        System.err.println("Argument must be an integer");
        System.exit(1);
    }
}

[SophieJohnson]

This simple application displays each of its command line arguments on a line by itself:
class Echo {
public static void main (String args[]) {
for (int i = 0; i < args.length; i++)
System.out.println(args[i]);
}

So hopefully this command line useful in your programming feature.
All the Best!!
Sophie Johnson

[Beter 2 Burn Out]

Thank you for replying me and giving me explanation about what are Command-Line Arguments in Java and explanation it in details.