There are two types of API s available with Android for a particular version of platform. They are the Android API and the Google API.  As an example the Android API level 15 includes Android 4.0.3 API and the Google APIs for the same platform 4.0.3. If you install only the SDK Platform of the Android 4.0.3(API 15) using the Android SDK Manager you can create a normal android application. But if you want to create a Map application you’ll have to install the Google APIs by Google Inc. The reason is that the normal Android API contains only the android.jar and in the Google APIs it provides the maps.jar in addition to the android.jar.

Hello World Android application

You can create a simple android application by following the steps below.

1. Select File -> new project ->Android ->Android Project -> fill the project details in the new window.
2.  Project name : Hello Android
3. Select Built target : Android 2.3.3 (API 10)   – This will define the target SDK . This is usually the android SDK compiled against and used to indicate version the developer primarily tested and designed for.
4. Application name: Hello World
5. Package: example.app
6. Create Activity : HelloAndroidActivity
7. Min Version: 4   – This will define minimum platform version supported by the application.