input exception error in Java -

i keep getting exception error. simple code. why getting exception error?

class thirdprogram { public static void main(string[] args)  {   system.out.println("hello out there.");   system.out.println("i add 2 numbers you.");   system.out.println("enter 2 whole numbers on line.");    int n1, n2;    scanner keyboard = new scanner(system.in);   n1 = keyboard.nextint();   n2 = keyboard.nextint();    system.out.println("the sum of 2 numbers is");   system.out.println(n1 + n2);  } } 

when use:

http://ideone.com/

do following:

step 1

make sure select java on left.

step 2

enter code:

import java.util.scanner;   class thirdprogram { public static void main(string[] args)  {   system.out.println("hello out there.");   system.out.println("i add 2 numbers you.");   system.out.println("enter 2 whole numbers on line.");    int n1, n2;    scanner keyboard = new scanner(system.in);   n1 = keyboard.nextint();   n2 = keyboard.nextint();    system.out.println("the sum of 2 numbers is");   system.out.println(n1 + n2);  } } 

step 3

before hit submit button, click click here enter input (stdin) or additional note. once click it, 2 boxes appear. in first box ( enter input (stdin) ), enter:

5  7 

make sure press enter after 7.

step 4

then hit submit. results load @ bottom.

note:

you should download , use ide instead (like jgrasp or eclipse). ides come compilers , allow enter input in after run program console.