Android - An Open Handset Alliance Project
Android allows you to access core mobile device functionality through standard API calls.

Android SDK
Developers can create applications for the platform using the Android SDK. Applications are written using the Java programming language and run on Dalvik, a custom virtual machine designed for embedded use which runs on top of a Linux kernel.

Dalvik Debug Monitor Server
Android ships with a debugging tool called the Dalvik Debug Monitor Service (DDMS), which provides port-forwarding services, screen capture on the device, thread and heap information on the device, logcat, process, and radio state information, and more features.