connect 2 package in android

1<manifest package="com.example" . . . >
2  <application . . .>
3    <activity android:name=".package1.Activity1" . . . />
4    <activity android:name=".package2.Activity2" . . . />
5  </application>
6</manifest>

1com.example.package1.Activity1
2com.example.package2.Activity2