java find objects with unique attribute in a list
<p>I have a list of objects in the following form</p>

<pre><code>Person object with attributes and values
name=x, state=va
name=x, state=nj
name=x, state=va
name=x, state=va
name=x, state=md
name=x, state=va
</code></pre>

<p>I want to find the unique state values as an array or list. Do Google collection or Java provide this feature? Or do I have to loop through all objects and find the unique state values?</p>
