Android Architecture

1. Applications:

These are applications written in Java

1. Some of basic applications includes an calendar, email client, SMS program, maps, making phone calls, accessing the Web browser, accessing your contacts list and others.

2. easy for device hardware, access location information, run background services, set alarms, add notifications to the status bar, and much, much more.

3. rest all layers are used by Google programmers, developers and hardware manufacturers.

2. Application Framework:

This is the skeleton or framework which all android developers has to follow.

1. used to build an application
   
2. to access data from other applications
   
3. Resource Manager
   
4. Notification Manager
5. Activity Manager

3. Libraries:

1. consists of Android libraries written in C, C++, and used by various system
   
2. to handle different kinds of data
   
3. Some of these libraries includes  media, graphics, 3d, SQLite, web browser library etc.
   

4. Runtime Android:

1. Every Android application runs in its own process, with its own instance of the Dalvik virtual machine.
   
2. Using Dalvik, a device can run multiple VMs efficiently.
   
3. The Dalvik virtual machine is a register-based virtual machine, designed and written by Dan Bornstein with contributions from other Google engineers.
   
4. The Dalvik VM executes files in the Dalvik Executable (.dex) format which is optimized for minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler that have been transformed into the .dex format by the included "dx" tool.
   

5. Kernel – Linux:

“Linux kernel for underlying functionality such as threading and low-level memory management."
Let me make it simple for you, without Linux, there is no Android.