Error: Could not find or load main class

package com.karthi;
public class HelloWorld {

public static void main(String[] args) {
// TODO Auto-generated method stub

System.out.println("Hello World");

}

}

/////

C:\Users\rakarthikeyan\Desktop\workspace\HelloWorld\bin\com\karthi>java HelloWorld
Error: Could not find or load main class HelloWorld

/// Fix - execute along with package name ie. use fully-qualified name ///

C:\Users\rakarthikeyan\Desktop\workspace\HelloWorld\bin>java com.karthi.HelloWorld

Hello World