Android - An Open Handset Alliance Project
Android allows you to access core mobile device functionality through standard API calls.
Android Debug Bridge
Android Debug Bridge (adb) is a versatile tool that lets you manage the state of a device or emulator.
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.
Dalvik: How Google routed around Sun.s IP-based licensing restrictions on Java ME
Dalvik is a virtual machine, just like Java's or .NET.s, but it's Google's own and they're making it open source without having to ask permission to anyone.