Android Architecture Layers

The Four Layers

Android is organised in layers, each with a clear responsibility:

1. Linux Kernel - memory, process and driver management; the security boundary of the platform.

2. Native Libraries - C/C++ libraries such as SQLite, WebKit and OpenGL used by the framework.

3. Android Runtime - the Dalvik/ART virtual machine that runs apps in their own process.

4. Application Framework - the Java APIs apps use: Activity Manager, Window Manager, Content Providers, View System and Package Manager.

5. Applications - the built-in and third-party apps on top.

Key Points

• Layers protect the platform: apps cannot touch the kernel directly.
• The framework provides the building blocks every app reuses.
• The runtime isolates each app as its own process and uid.