what's in the (package) name org.example.hello?
<p>I'm familiar with C++ but never used Java. I've just started learning Android development. In most of the basic tutorials I've gone through mentioned packages names like org.example.hello. I know they are some sort of unique identifiers but</p>

<ol>
<li>How should I choose these packages names? Are there any guidelines?</li>
<li>Is there anything special I need to keep in mind if I'm developing a commercial application?</li>
<li>How can I make separate re-usable libraries and pack them in different packages/applications?</li>
</ol>

<p>thanks.</p>
