Building Android

• Jack was introduced as a Toolchain from Marshmallow onwards for Apps and Frameworks.
  • Uses a Java VM for compilation of Java Source Code ‘.java’ to ‘.dex’ (Dalvik Executable) files
  • Recommended for Systems with >8GB RAM.
  • Systems with 4GB RAM can use it too, but it may cause lag during compilation, so using Swap is recommended for such users.
• Ninja was introduced from Android Nougat (7.x.x) as an alternative Build System.
  • No compatibility requirements.
  • Some features of it are quicker incremental builds, and showing progress of the build on compilation
• Companions for Ninja, which were also introduced in Nougat are…
  • Kati
    This is a tool which helps in generation of a .ninja file, in BluePrint Language, which guides through the build process…
  • Soong
  • BluePrint
    A Language, possible successor of the Makefile Language

So, the ways of building Android are…

• Using Normal Build System
  • with Jack Toolchain (Marshmallow onwards)
  • without Jack Toolchain (Till Nougat)
• Using Ninja Build System
  • with Jack Toolchain (Nougat onwards)
  • without Jack Toolchain (Nougat onwards) - Reported Non-Working by Developers

Setting up Android BuildSystem Environment

There are 3 ways (commands) of Setting up the Build Environment

lunch - Sets the Device Target which is specified by the user
breakfast - Syncs the Device Dependencies + lunch
brunch - breakfast + Starts the Build

Device Dependencies are synced by looking for a file named [rom_name].dependencies which specifies the same. It’s written in JSON.
brunch starts the build immediately after Setting the Environment

Usage of each of them

lunch rom_device-buildtype

breakfast device buildtype

brunch device

rom - ROM’s codename in source
device - Device’s Codename
buildtype - Either of these values -> user, eng, userdebug

Explanation of Values of buildtype is done HERE

Build Type	Use
user	limited access; suited for production
userdebug	like “user” but with root access and debuggability; preferred for debugging
eng	development configuration with additional debugging tools

Where userdebug is the preferably used for a Public Custom ROM Release. Debugging Tools in this Build are enough for normal debugging. eng is only used for debugging non-working things, and not to be publicly released.