Is it possible to integrate AdMob without the external library? I have seen AdMob in android SDK Manager. AdMob library uses quite lot of memory in my app.
You need to use the AdMob library (GoogleAdMobAdsSdk-xxx.jar file) to integrate AdMob ads into your app.
It adds a bit of size (the latest jar GoogleAdMobAdsSdk-6.4.1.jar is 345 kB) but you need that for your ads.
This is the page with integration instructions: https://developers.google.com/mobile-ads-sdk/docs/?hl=en_GB#android