ADB stands for Android Debug Bridge. It is a command line tool that is used to communicate with the emulator instance. ADB can control your device over USB from a computer, copy files back and forth, install and uninstall apps, run shell commands, and more. It is a client-server program that includes three components:

• A client, which runs on your development machine. You can invoke a client from a shell by issuing an ADB command. Other Android tools such as DDMS also create ADB clients.

• A server, which runs as a background process on your development machine. The server manages communication between the client and the ADB daemon running on an emulator or device.

• A daemon, which runs as a background process on each emulator or device instance.