How to share my jar utility with selected buddies only?
<p>I have made some general utilities(jars) for some general purposes.
Some of my friends want these utilities for their use.
I am ready to share my stuff (free of cost), but afraid they don't re-distribute it further.</p>

<p>Is their something in java as described in the following code for my jar's class files.</p>

<pre><code>public class UtilityClass{

            static{

             long secretCode = 7534759 ;
             //a hardcoded long value (hardcoded by me for my friend)
             //related to friend's Computer System which either
             // don't changes untill he reformats his computer
             // or is something like motherboard serial number or etc..etc...

             long buddiesSystemSecretCode = getSecretCode() ;

             if( !(buddiesSystemSecretCode == secretCode) ){
              System.exit(1) ;
             }
            }

            private static long getSecretCode(){
             long secretCode = 0 ;

             //any java code to get friend's System hardware specific code

             return secretCode ;
            }
        }
</code></pre>
