What is inside the AOSP?

Before we move to the details, let's take a look at the top level of the AOSP source code tree again:

The following table gives a brief description about each folder. We will look at some of them throughout this book:

Directory	Description
packages	Stock Android applications.
libcore	Core Java library. Apache Harmony is used before Nougat. OpenJDK is used with Nougat. Some features of Java 8 are used in Nougat.
frameworks/*	Android framework core components.
frameworks/base/services	Android system services.
art	Android runtime.
dalvik	Dalvik virtual machine.
libnativehelper	Helper functions for use with JNI.
system/*	Native services and libraries.
system/core	A minimal Linux system to boot Android.
bionic	C library.
external	External projects imported into the AOSP. It includes both the HAL layer and system services.
hardware	HAL and hardware libraries.
device	Device-specific files and components.
bootable	Recovery and bootloader.
abi	Minimal C++ runtime type information support.
build	Build system...