about mechanisms on creating a class object
<p>I saw a class "AttributeSelectedClassifier" was once created in the following ways:</p>

<pre><code>AttributeSelectedClassifier classifier = new AttributeSelectedClassifier();

classifier.setClassifier(base);
classifier.setEvaluator(eval);
</code></pre>

<p>This above one looks natural to me. But how about the following one.</p>

<pre><code>classifier = new AttributeSelectedClassifier();
((AttributeSelectedClassifier)classifier).setClassifier(base);
((AttributeSelectedClassifier)classifier).setEvaluator(eval);
</code></pre>

<p>I think it should be right, but I am not quite sure about the way of of defining classifier as ((AttributeSelectedClassifier)classifier), how to understand this usage?</p>
