hashset datatype
<p>How to declare a headset using double as datatype?</p>

<pre><code>public HashSet priceSet() {
    Set&lt;double&gt; hSet = new HashSet&lt;double&gt;();  //&lt;==== netbeans warn this line
    for (Map.Entry&lt;String, Tablet&gt; entry : tableMap.entrySet()) {     
        hSet.add(entry.getValue());
    }        

    return (HashSet) hSet;
}
</code></pre>

<p>what's the problems of this line?
Set hSet = new HashSet();</p>
