Build Android Platform

1) Get JDK 5.0, update 12 or higher. Java 6 is not supported.
In Ubuntu 9.10, use the Ubuntu 9.04 repositories to get Java5
add the following repositories to /etc/apt/sources.list
deb http://us.archive.ubuntu.com/ubuntu/ jaunty multiverse
deb http://us.archive.ubuntu.com/ubuntu/ jaunty-updates multiverse

2) Setup development environment
$ sudo apt-get update
$ sudo apt-get install git-core gnupg sun-java5-jdk flex bison gperf libsdl-dev libesd0-dev libwxgtk2.6-dev build-essential zip curl libncurses5-dev zlib1g-dev valgrind

3) Installing Repo
Create ~/bin directory and add it to PATH
$ cd ~
$ mkdir bin
$ set PATH=~/bin:$PATH

Download the repo script and make sure it is executable:
$ curl http://android.git.kernel.org/repo >~/bin/repo
$ chmod a+x ~/bin/repo

4) Initializing a Repo client
$ mkdir mydroid
$ cd mydroid
$ repo init -u git://android.git.kernel.org/platform/manifest.git

5) Getting the files
$ repo sync

6) Building the code
$ cd ~/mydroid
$ make

7) Testing
export ANDROID_PRODUCT_OUT=~/mydroid/out/target/product/generic
cd ~/mydroid/out/host/linux-x86/bin
./emulator

8) Building SDK
$ cd ~/mydroid
$ make sdk