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How to get command line arguments?

When creating a Java application we will sometime need to pass a couple parameters when the program is executed. To get the passed parameter from the command line we can read the argument passed to the main method just as the signature above. As you know to make a class executable you need to create a method as follow:

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

As you can see, this method take an array of String as the parameter. You can guess that this array is the parameter that we passed in the command line.

package com.javacoderanch.example.fundametal;

public class ArgumentParsingExample {
    public static void main(String[] args) {
        for (int i = 0; i < args.length; i++) {
            System.out.println("Argument " + (i + 1) + " = " +
                    args[i]);
        }

        // 
        // If you want to check if the number of supplied parameters
        // meet the program requirement you can check the size of 
        // the arguments array.
        //
        if (args.length < 3) {
            System.out.println(
                    "You must call the program as follow:");
            System.out.println(
                    "java ArgumentParsingExample arg1 arg2 arg3");

            //
            // Exit from the program with an error status, for 
            // instance we return -1 to indicate that this program 
            // exit abnormally
            //
            System.exit(-1);
        }

        System.out.println("Hello, Welcome!");
    }
}