Android applications are written in the Java programming language. The Android SDK tools compile the code—along with any data and resource files—into an Android package, an archive file with an .apk suffix. All the code in a single .apk file is considered to be one application and is the file that Android-powered devices use to install the application.
From Android Application Fundamentals
Resources of Android App Development:
The Official Android Developer’s Guide: From Google
Introduction to Android development – IBM’s Guide
How to get started: TechRepublic’s Tutorial
Basics and pre-requisites: XLNCSolution’s Guide
Android Development Tutorial for Gingerbread: From Lars Vogel
Presentations regarding Android Application Development
I hope these links help. 🙂
