Q:

What are the Java components necessary to posting an Ad from Admob? 

Does one simply include the xml for an ad only, or is there something else to add in Java? 
In my situation, this is what I currently have for the ad in my xml:
<com.google.ads. AdView
    android:id="@+id/ad"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"        
    ads:adSize="BANNER"
    ads:adUnitId="ca-app-pub-XXXXXXXXXXXXXXX/XXXXXXXXXX"
    ads:testDevices="TEST_EMULATOR"
    ads:loadAdOnCreate="true"
    android:layout_alignParentBottom="true">
</com.google.ads. AdView>

Is there something missing in the MainActivity.java class? 

A:

This link should help you: AdMob Android Integration.   It covers everything from importing the library to updating the manifest to the XML layout and onCreate.   Should get you up and running. 