Correct way of implementing class impossible to instantiate
<p><strong>Short:</strong></p>

<p>Do I need to do something else but leaving out constructor?</p>

<p><strong>Long:</strong></p>

<p>I want to implement class which cannot be instantiate. I have find example in Math class here: <a href="http://docs.oracle.com/javase/6/docs/api/java/lang/Math.html" rel="nofollow">http://docs.oracle.com/javase/6/docs/api/java/lang/Math.html</a></p>

<p>So I would write same thing:</p>

<pre><code>public final class MyClass{

    public static int doubleMe(int x){
        return 2*x;
    }
}
</code></pre>

<p>Constructor is absent, so instantiation should be impossible. </p>

<p>But I am not sure about making my class final. Maybe (not necessarily) I would like to extend it in the future (eg. public class myClassB extends myClass) and this keyword will prevent it - so does it have to be there?.</p>
