Java - Command Line Arguments / Chapter - 8 /Language Fundamental

java command line arguments 

1.The arguments which are passing from command-prompt are called command-line arguments.
With these command-line arguments, JVM will create an array & by passing that array as arguments
JVM will call main( ) method.
for  example:-
class Test
{

      public static void main(String [ ] args)

     {

       System.out.println("javabychetan.blogspot.com ");

       for(int i=0;i<args.length;i++)

           {

           System.out.println(args[i]);

           }

       }

}

The output of the program is:

javabychetan.com
A
B
C
Runtime-Exception ArrayIndexOutOfBoundException

Why Runtime-Exception ??
Because at args[0]=A,args[1]=B,args[2]=c,
But at  args[3] is nothing that's why we are getting Runtime-Exception ArrayIndexOutOfBoundException.

Note: -If we replace <= with < then we won't get any Runtime-Exception. 

2. The main advantage of command line arguments is we can customize the behavior of the main( ) method.
The String is taken as an argument type because:-

• From String to any other type we can able to convert.


• The string is the most commonly used object in java.

example 2:-

class Test
{
public static void main(String [ ] args)
{
String [ ] argh={"A","B","C"};
args=argh;
for(String s:args)
{
System.out.println(s);
}
}
}
Now

javac     Test.java
java   X  Y  Z

Output is:-

A
B
C

After
args=argh;