Android source code architecture

The Android platform consists of several projects already in progress. These projects can be divided into three categories:
Core projects: These projects make up the foundation of the Android platform.
External projects: The Android Open Source Project makes use of many other open source projects.
Packages: These projects are standard Android applications and services.

Core	Description
bionic	C runtime: libc, libm, libdl, dynamic linker
bootloader/legacy	Bootloader reference code
build	Build system
dalvik	Dalvik virtual machine
development	High-level development and debugging tools
frameworks/base	Core Android app framework libraries
frameworks/policies/base	Framework configuration policies
hardware/libhardware	Hardware abstraction library
hardware/ril	Radio interface layer
kernel	Linux kernel
prebuilt	Binaries to support Linux builds
recovery	System recovery environment
system/bluetooth	Bluetooth tools
system/core	Minimal bootable environment
system/extras	Low-level debugging/inspection tools
system/wlan/ti	TI 1251 WLAN driver and tools

App

AlarmClock

Browser

Calculator

Calendar

Camera

Contacts

Email

GoogleSearch

HTML Viewer

IM

Launcher

Mms

Music

PackageInstaller

Phone

Settings

SoundRecorder

Stk

Sync

Updater

VoiceDialer

Provider

CalendarProvider

ContactsProvider

DownloadProvider

DrmProvider

GoogleContactsProvider

GoogleSubscribedFeedsProvider

ImProvider

MediaProvider

SettingsProvider

SubscribedFeedsProvider

TelephonyProvider