• Ubuntu 14.04 +
• OpenJDK/JDK
• A Nexus/Pixel phone

Assuming you already have a newer Ubuntu system and a Google Son phone, we’ll start by installing the JDK.

This article was written by MichaelX, whose blog address is blog.csdn.net/xiong_it.

Warning: Do not use the Oracle JDK to compile newer AOSP versions (API 21+/Android 5.0 and above). You will get an error when preparing to make clobber.

Checking build tools versions... ************************************************************* You asked for an OpenJDK based build but your version is Version "1.8.0_121" Java(TM) SE Runtime Environment(build 1.8.0_121-B13)Java HotSpot (TM) 64-bit Server VM(build 25.121 - bl3), mixed mode). * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * the build/core/main. Mk: 230: *** stop.Copy the code

The choice of JDK version: It depends on the Android version you want to build

• AOSP OpenJDK 8
• Android 5.x (Lollipop) – Android 6.0 (Marshmallow):OpenJDK 7
• Android 2.3.x (Gingerbread) – Android 4.4.x(KitKat):Java JDK 6
• Android 1.5 (Cupcake) – Android 2.2.x (Froyo): Java JDK 5

The blogger wants to build for Android 7.0, so he needs to use OpenJDK 8.

OpenOJDK 8 on github 2. Openopenjdk 8 on Github 3. Add a PPA to install OpenJDK

$ sudo add-apt-repository ppa:openjdk-r/ppa
$ sudo apt-get update

$ sudo apt-get install openjdk-8-jdk

$ sudo update-alternatives --config java
$ sudo update-alternatives --config javacCopy the code

If you are running Ubuntu 15.04 or newer, run the following command to install OpenJDK 8

$ sudo apt-get update
$ sudo apt-get install openjdk-8-jdkCopy the code

Linux uses the following command to view all JDK versions on the machine

$ michaelx@michaelx-ThinkPad:~/AOSP_NBD91Z$ update-java-alternatives -l
// Print out the installed JDK version below
java-1.8. 0-openjdk-amd64 1069 /usr/lib/jvm/java-1.8. 0-openjdk-amd64Copy the code

Linux sets the default JDK commands

// Set the default to OpenJDk8, which must be used here
$ sudo update-java-alternatives -s java-1.8. 0-openjdk-amd64
// Set the default to Oracle JDk8
$ sudo update-java-alternatives -s java-8-oracle
// Set the default to Oracle JDk7
$ sudo update-java-alternatives -s java-7-oracleCopy the code

Ubuntu 14.04: OpenJDK 8

update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
Copy the code

This prompt is ignored and can be ignored.

Check the Java version. If the following message is displayed, the JDK environment is ok.

$ java -version

openjdk version "1.8.0 comes with _111"
OpenJDK Runtime Environment (build 1.8. 0_111-8u111-b14-3~14.041.-b14)
OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode)Copy the code

If you really can’t switch the default JDK, do what bloggers do and uninstall the Oracle JDK.

Ps: I don’t know what this does, but it is officially recommended, in order to make usb devices accessible to ordinary users.

$ wget -S -O - http://source.android.com/source/51-android.rules | sed "s/<username>/$USER/" | sudo tee >/dev/null /etc/udev/rules.d/51-android.rules; sudo udevadm control --reload-rulesCopy the code

Since you need to download the Android source code, you will need to prepare a Google Gmail email address beforehand. Run the following command to configure the git user name and Gmail.

Get the build platform ready

$ cd AOSP_NBD91Z
$ source build/envsetup.sh
Or, the command above is equivalent to the command below
$ . build/envsetup.shCopy the code

Select compilation Platform

This command can be executed only after the preceding command is executedlunch



I chose 21 because I had a Nexus 6 (Shamu)

On the differences between the modes

• User Indicates the normal mode for common users
• Userdebug has root privileges and more debugging functions. Other functions are the same as user mode
• The best option for ENG developers, with many additional debugging tools

Run make to compile the AOSP source code, or use the -j option to specify the number of parallel compilation threads

Compile with 6 threads. The official recommended maximum number of parallel threads is between J16 and J32.
$ make -j6 

Please do what you can according to your CPU performance. The blogger used -j16 which caused the GUI interface and terminal to freeze, and could only forcibly shut down my SSD for 30s.Copy the code

Another long wait. If nothing goes wrong, then whatout/target/product/[product_name]/Img, recovery.img, etc., will be added to the directory, and you can happily swipe the machine.

Below are the various image files generated and others.

[ 6% 2375/35393] target Java: icu4j (out/target/common/obj/JAVA_LIBRARIES/icu4j_intermediates/classes)

Note: Some input files use or override a deprecated API.

Note: Recompile with -Xlint:deprecation for details.

Note: external/icu/icu4j/main/classes/core/src/com/ibm/icu/impl/Relation.java uses unchecked or unsafe operations.

Note: Recompile with -Xlint:unchecked for details.

[ 6% 2394/35393] host C++: libLLVMMC_32 <= external/llvm/lib/MC/MCDwarf.cppninja: fatal: fork: Cannot allocate memory

make: *** [ninja_wrapper] Error 1

[  5% 1883/35393] Docs droiddoc: out/target/common/docs/api-stubs
FAILED: /bin/bash out/target/common/docs/api-stubs-timestamp.rsp
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000000bdb80000.72876032.0) failed; error='Cannot allocate memory' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 72876032 bytes for committing reserved memory.
# An error report file with more information is saved as:
# /home/michaelx/AOSP_NBD91Z/hs_err_pid508.log
[  5% 1883/35393] Docs droiddoc: out/target/common/docs/system-api-stubs
DroidDoc took 27 sec. to write docs to out/target/common/docs/system-api-stubs
ninja: build stopped: subcommand failed.
make: *** [ninja_wrapper] Error 1Copy the code

There are three solutions to running out of memory:

1. Increase machine memory
2. Adding a swap partition
3. Modify the prebuild/ SDK /tools/jack-admin file

The first way is not to say, add root memory to the machine, trench exclusive. The second way: increase of swap: hancj.blog.51cto.com/89070/19791… The third way:

# backup jack - admin
$ cp prebuild/sdk/tools/jack-admin ~/Docments/jack-admin.original

# Change the jack-admin file
$ vim prebuild/sdk/tools/jack-admin

# start-server method, my jack-admin in line 443, modify this method with a sentence:
# JACK_SERVER_COMMAND="java -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -cp $LAUNCHER_JAR $LAUNCHER_NAME"
# Change to the following line to increase the Java heap size.
JACK_SERVER_COMMAND="java -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -Xmx8000M -cp $LAUNCHER_JAR $LAUNCHER_NAME"Copy the code

The above increase of -XMx8000m means that the maximum memory used by Java heap at runtime is not more than 8000M. This value is the result obtained by the author after many tests. 2048M and 4096M still failed to be compiled, and 8000M passed compilation, which may be largely related to the author’s own hardware limitations

Another way to modify: change the variable on line 29 of jack-admin: JACK_SERVER_VM_ARGUMENTS="${JACK_SERVER_VM_ARGUMENTS:= -dfile. encoding -utf-8 -xx :+TieredCompilation}"  JACK_SERVER_VM_ARGUMENTS="${JACK_SERVER_VM_ARGUMENTS:=-Dfile.encoding-UTF-8 -XX:+TieredCompilation -Xmx8000M}" But this modification still didn't work, and the compilation failed.Copy the code

The author is to try the second, three ways to solve.

[37% 13421/35393] Ensure Jack Server is installed and started FAILED: /bin/bash -c “(prebuilts/sdk/tools/jack-admin install-server prebuilts/sdk/tools/jack-launcher.jar Prebuilts/SDK/tools/jack – server – 4.8 ALPHA. Jar 2 > &1 | | (exit 0)) && (JACK_SERVER_VM_ARGUMENTS = \ “- Dfile. Encoding = utf-8 -XX:+TieredCompilation\” prebuilts/sdk/tools/jack-admin start-server 2>&1 || exit 0 ) && (prebuilts/sdk/tools/jack-admin The update server prebuilts/SDK/tools/jack – server – 4.8 ALPHA. Jar 4.8 ALPHA 2 > &1 | | && exit 0) (prebuilts/SDK/tools/jack – admin update jack prebuilts/SDK/tools/jacks/jack – 2.28. The jar 2.28 RELEASE | | exit 47; Prebuilts/SDK/tools/jack – admin update jack prebuilts/SDK/tools/jacks/jack – 3.36. CANDIDATE. Jar 3.36. CANDIDATE | | exit 47; Prebuilts/SDK/tools/jack – admin update jack prebuilts/SDK/tools/jacks/jack – 4.7 BETA. Jar 4.7 BETA | | exit 47) “jack server already installed in “/home/michaelx/.jack-server” Launching Jack server java -XX:MaxJavaStackTraceDepth=0 -Djava.io.tmpdir=/tmp -Dfile.encoding=UTF-8 -XX:+TieredCompilation -cp /home/michaelx/.jack-server/launcher.jar com.android.jack.launcher.ServerLauncher Jack server failed to (re)start, try ‘jack-diagnose’ or see Jack server log No Jack server running. Try ‘jack-admin start-server’ No Jack server running. Try ‘jack-admin start-server’ [ 37% 13421/35393] target thumb C++: libicui18n <= external/icu/icu4c/source/i18n/coptccal.cpp [ 37% 13421/35393] target thumb C++: libicui18n <= external/icu/icu4c/source/i18n/compactdecimalformat.cpp [ 37% 13421/35393] target thumb C++: libicui18n <= external/icu/icu4c/source/i18n/cpdtrans.cpp ninja: build stopped: subcommand failed.

Jack Server failed to (re)start

$ cd /prebuild/sdk/tools/

$ jack-admin stop-server
$ jack-admin start-serverCopy the code

Thanks to AOSP website: source.android.com/source/init… AskUbuntu:askubuntu.com/questions/7… CSDN:blog.csdn.net/brightming/…

Etc… .