when i run a simple program on package it shows error my program is

package world;
public class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello World");
  }
}

i ve stored it in c:\world

so i compile it by c:\world> javac HelloWorld.javaprint("code sample");

it compiles succesfully but when i do c:\world>java world.HelloWorld

it shows the foll error

Caused by: java.lang.ClassNotFoundException: world.HelloWorld at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) Could not find the main class: world.HelloWorld. Program will exit.

plzzz help