problem with compiling on a mac terminal

Hi , i am new to java ( know c++ ) and im begining to learn java , i am using mac os x terminal and i got this code from a tutorial:

class myfirstjavaprog

{

public static void main(String args[])

{

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

}

}

i saved it as hellowworld.java

then i did the folowing things:

javac hellowworld.java (it worked fine)

and then i did java hellowworld ( as the tutorial says) and i get the folowing error messege :

exception in thread "main" java.lang.NoClassDeFoundError: hellowworld

thanks for reading and hope you can help me !

sincerly Kil

[656 byte] By [kilmuntad] at [2007-9-30 18:27:52]