In Java, how do I ensure a dummy class is never used?
<p>I am working on a project in which, to resolve a versioning issue, I am creating many classes which will never be tested and must not ever be used - they just need to be there to keep the compiler happy.  I'd like to make sure they are never used.  This morning I had the idea of throwing an exception in a static initialization block:</p>

<pre><code>public class Dummy {

    static {
        throw new IllegalStateException("Do not use this class!");
    }
}
</code></pre>

<p>But the compiler doesn't like it.  Can you think of any way to do this?</p>

<p><strong>EDIT:</strong> to be clear (my fault I wasn't clear before), these won't just be empty classes.  There will be all sorts of code in here, and by "keep the compiler happy" I did indeed mean that elsewhere I will be instantiating them, calling methods etc etc.  I want this code elsewhere to compile but fail at runtime.  I have accepted Jon's answer but will also be using <code>@Deprecated</code> and documenting extensively as appropriate.</p>
