[Java2]

I have managed to succesfully compile the following java program and it has created the class file correctly.

However when I try to run the program DOS comes up with this error.

Exception in thread "main" java.lang.NoClassDefFoundError: then the file name

this is the code of the main file

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