解决编译android8.1系统时jack失败的问题

当编译android8.1系统时，有时之前编译正常的，突然出现：

FAILED: setup-jack-server 
/bin/bash -c "(prebuilts/sdk/tools/jack-admin install-server prebuilts/sdk/tools/jack-launcher.jar prebuilts/sdk/tools/jack-server-4.11.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 update server prebuilts/sdk/tools/jack-server-4.11.ALPHA.jar 4.11.ALPHA 2>&1 || exit 0 ) && (prebuilts/sdk/tools/jack-admin update jack prebuilts/sdk/tools/jacks/jack-4.32.CANDIDATE.jar 4.32.CANDIDATE || exit 47 )"
Jack server already installed in "/home/zhaojingrong/.jack-server"
Communication error with Jack server (60), try 'jack-diagnose' or see Jack server log
Failed to authenticate Jack server certificate. Try 'jack-diagnose'
Failed to authenticate Jack server certificate. Try 'jack-diagnose'
...............................................................
ninja: build stopped: subcommand failed.
11:50:50 ninja failed with: exit status 1

这个时候解决的办法如下：
1、修改 prebuilts/sdk/tools/jack-admin 文件，增加 ‘-Xmx’。如下我使用的是 -Xmx4G

-      JACK_SERVER_COMMAND="java -XX:MaxJavaStackTraceDepth=-1 -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -cp $LAUNCHER_JAR $LAUNCHER_NAME"
+      JACK_SERVER_COMMAND="java -XX:MaxJavaStackTraceDepth=-1 -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -Xmx4096M -cp $LAUNCHER_JAR $LAUNCHER_NAME"

2、修改/home/.jack-setting文件，将SERVER_PORT_SERVICE和SERVER_PORT_ADMIN值从新修改一个端口号，如下：

$ vim /home/.jack-setting
SERVER_PORT_SERVICE=28076 
SERVER_PORT_ADMIN=28077
換成：
SERVER_PORT_SERVICE=28023
SERVER_PORT_ADMIN=28022

3、修改/home/jack-server/config.properties文件，将SERVER_PORT_SERVICE和SERVER_PORT_ADMIN值从新修改一个端口号，跟/home/.jack-setting的端口号保持一致。如下：

$ vim /home/jack-server/config.properties
SERVER_PORT_SERVICE=28076 
SERVER_PORT_ADMIN=28077
換成：
SERVER_PORT_SERVICE=28023
SERVER_PORT_ADMIN=28022

4、先杀掉jack-admin服务，然后再全系统编译即可，如下：

$ ./prebuilts/sdk/tools/jack-admin kill-server

以上的主要原因是，jack服务器和客户端的端口号被其它同事占用导致的，修改成同一网段内部其它同事没使用的端口号即可，防止出现jack编译的时候，有编译报错：Out of memory error的错误，将jack服务编译时单个进程最大修改到4G(加上这个参数-Xmx4G)，注意编译机器的内存必须大于4G内存。