Activity name in AndroidManifest.xml
<p>Is it required to start activity name with dot ('.')  in manifest file.? for example activity 
 ContactManager starts with '.'</p>

<pre><code>&lt;activity android:name=".ContactManager" android:label="@string/app_name"&gt;
</code></pre>

<p>where as the activity ContactAdder is without dot</p>

<pre><code>&lt;activity android:name="ContactAdder" android:label="@string/addContactTitle"&gt;
</code></pre>

<p>in the manifest file of ContactManager sample <a href="http://developer.android.com/resources/samples/ContactManager/AndroidManifest.html">http://developer.android.com/resources/samples/ContactManager/AndroidManifest.html</a> </p>

<p>UPDATE: If activity name starts with . it is appended to package name to become fully qualified name, but what happens if it doesn't start with '.'</p>
