Compile Android Operating System Program

1. Install java jdk 5

Open /etc/apt/sources.list with a text editor like gedit:

sudo gedit /etc/apt/sources.list

Add the following lines to the end of the file then save it and close:

## For sun-java5-jdk

deb http://us.archive.ubuntu.com/ubuntu/ jaunty multiverse

 deb http://us.archive.ubuntu.com/ubuntu/ jaunty-updates multiverse

Update the packages lists and install sun-java5-jdk:

sudo apt-get update

sudo apt-get install sun-java5-jdk

2. Setup the environment variables for Java 

sudo gedit ~/.bashrc

add the following to the end of the file:

export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun

export JRE_HOME=${JAVA_HOME}/jre

export JAVA_PATH=${JAVA_HOME}/bin:${JRE_HOME}/bin

export ANDROID_JAVA_HOME=${JAVA_HOME}

export HOME_BIN=~/bin

export PATH=${PATH}:${JAVA_PATH}:${HOME_BIN}

export CLASSPATH=.:$CLASSPATH:${JAVA_HOME}/lib:${JRE_HOME}/lib

close the file, and update the list with the following command:

source ~/.bashrc

to check the variables, use echo command or env, for example:

echo $JAVA_HOME

env

To alter the javadoc link to java 5 version, use the following command:
cd /etc/alternatives

sudo rm javadoc.1.gz

sudo rm javadoc

sudo ln -s /usr/lib/jvm/java-1.5.0-sun/man/man1/javadoc.1.gz javadoc.1.gz

sudo ln -s /usr/lib/jvm/java-1.5.0-sun/bin/javadoc javadoc

if something is still wrong, you can also change the javac/java link to java 5 version:

sudo ln -s /usr/lib/jvm/java-1.5.0-sun/bin/javac javac

sudo ln -s /usr/lib/jvm/java-1.5.0-sun/bin/java java

If you install more than one java version, use can use the following command to choose the right one.
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-1.5.0-sun/bin/java 300

sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/java-1.5.0-sun/bin/javac 300

sudo update-alternatives --config java

To see the java version, use:

java -version

3. Install necessary tools

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

If something is wrong, you may find the following commands helpful:

sudo apt-get install make

sudo apt-get install gcc

sudo apt-get install g++

sudo apt-get install libc6-dev
sudo apt-get install patch

sudo apt-get install texinfo
sudo apt-get install zlib1g-dev

sudo apt-get install valgrind 

sudo apt-get install python2.6

4. Install repo ( to update android source) 

cd ~ && mkdir bin

curl http://android.git.kernel.org/repo >~/bin/repo

chmod a+x ~/bin/repo

Then initialize repo

mkdir android && cd android

repo init -u git://android.git.kernel.org/platform/manifest.git

During this process, you will be asked to enter your name and email. 

If it succeed, it will show like:

repo initialized in /android

5. Get the source

Use the following cmd to get the code, it will take very very long time, so you can go and have a snap.

repo sync

6. Compile android source code

You will get the output files in ~/android/out directory

cd ~/andoird

make

well, another snap.

7. run img using emulator

emulator is under ~/android/out/host/linux-x86/bin, 

ramdisk.img, system.img and userdata.img are under ~/android/out/target/product/generic

add the following variables:
export ANDROID_PRODUCT_OUT=~/android/out/target/product/generic

ANDROID_PRODUCT_OUT_BIN=~/android/out/host/linux-x86/binexport PATH=${PATH}:${ANDROID_PRODUCT_OUT_BIN}:${ANDROID_PRODUCT_OUT};

update:

source ~/.bashrc

then, try to use emulator to load the img

cd ~/android/out/target/product/generic

emulator -system system.img -data userdata.img -ramdisk ramdisk.img

if you see the android GUI, congratulations!

8. make a rom

zip -r update.zip .  

 sign the file (under java 6 version)

export JAVA_HOME=/usr/lib/jvm/java-6-sun

export JRE_HOME=${JAVA_HOME}/jre

export JAVA_PATH=${JAVA_HOME}/bin:${JRE_HOME}/bin

sudo update-alternatives --config java

java -version
If you are using java 6 now, put the autosign.jar under the folder 

java -jar autosign.jar update.zip update_signed.zip

Reference: http://hi.baidu.com/garnetttt/blog/item/13426d222f72b3ae4623e8f3.html