Command line arguments

• The group of strings what we are passing as an argument to the main method from the console or command line are known as command line arguments.
• Every command line argument would be accepted by the JVM in the form of a String object.
• JVM will always executes main method by passing object of an array of strings.
• JVM would never execute main method by passing null
• JVM always executes main as a thread. 

 

Program on command line arguments:

package com.instanceofjavaforus;

public class CommandLineArguents {

    public static void main(String args[]){
      
        System.out.println("Your first argument is: "+args[0]);
    }
  
}

• >javac CommandLineArguent.java
  
  >java CommandLineArguents
  
  OutPut:
  Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
      at com.instanceofjavaforus.CommandLineArguents.main(CommandLineArguents.java:8)
• >javac CommandLineArguent.java
  
  >java CommandLineArguents  instance
  
  OutPut:
  instance