在Android7.1编译过程中出现如下错误：
Starting build with ninjaninja: Entering directory `.' [ 0% 8/30301] Ensure Jack server is installed and startedJack server already installed in "/home/guochongxin/.jack-server"Launching Jack server java -XX:MaxJavaStackTraceDepth=-1 -Djava.io.tmpdir=/tmp -Dfile.encoding=UTF-8 -XX:+TieredCompilation -cp /home/guochongxin/.jack-server/launcher.jar com.android.jack.launcher.ServerLauncher[ 0% 10/30301] Building with Jack: out/target/common/obj/JAVA_LIBRARIES/libprotobuf-java-micro_intermediates/classes.jack[ 0% 12/30301] Building with Jack: out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/with-local/classes.dexFAILED: /bin/bash out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/with-local/classes.dex.rspOut of memory error (version 1.2-rc4 'Carnac' (298900 f95d7bdecfceb327f9d201a1348397ed8a843843 by android-jack-team@google.com)).GC overhead limit exceeded.Try increasing heap size with java option '-Xmx'.Warning: This may have produced partial or corrupted output.[ 0% 12/30301] Compiling SDK Stubs with Jack: out/target/comm...AVA_LIBRARIES/android_stubs_current_intermediates/classes.jackninja: build stopped: subcommand failed.make: *** [ninja_wrapper] Error 1
从上面的错误提示中可以看到如下一句：
Try increasing heap size with java option '-Xmx
按照上述发现的提示语句，我们对prebuilts/sdk/tools/jack-admin文件进行如下修改：1.找到如下语句：
JACK_SERVER_COMMAND="java -XX:MaxJavaStackTraceDepth=-1 -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -cp $LAUNCHER_JAR $LAUNCHER_NAME"
2.将上述语句修改为：
JACK_SERVER_COMMAND="java -XX:MaxJavaStackTraceDepth=-1 -Djava.io.tmpdir=$TMPDIR $JACK_SERVER_VM_ARGUMENTS -Xmx4096m -cp $LAUNCHER_JAR $LAUNCHER_NAME"
主要是添加了-Xmx4096m参数，接下来在源码目录下执行如下命令重启jack-admin服务：
./prebuilts/sdk/tools/jack-admin stop-server
./prebuilts/sdk/tools/jack-admin start-server
重启完jack-admin服务后，此时再重新执行编译命令就能编译通过了。
2.android build Communication error with Jack server (52)
解决方法：
使用命令重新启动jack
jack-admin stop-server
jack-admin start-server
3.如果jack-admin stop-server或者jack-admin start-server失败
1），通过修改配置文件~/.jack-settings，是个隐藏文件，设置不同的端口号：
# Server settings
SERVER_HOST=127.0.0.1
SERVER_PORT_SERVICE=8076
SERVER_PORT_ADMIN=8077
# Internal, do not touch
SETTING_VERSION=4
通过实验发现，单独修改配置文件$HOME/.jack-settings中的端口号没有效果，jack server一直启动失败，提示端口被占用：
com.android.jack.server.api.v01.ServerException: Problem while opening service port
at com.android.jack.server.JackHttpServer.start(JackHttpServer.java:611)
at com.android.jack.server.JackServerImpl.run(JackServerImpl.java:62)
at com.android.jack.launcher.ServerLauncher$3.run(ServerLauncher.java:391)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.BindException: Address already in use
at sun.nio.ch.Net.bind0(Native Method)
at sun.nio.ch.Net.bind(Net.java:433)
at sun.nio.ch.Net.bind(Net.java:425)
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
at com.android.jack.server.ServerParameters.openSocket(ServerParameters.java:88)
at com.android.jack.server.ServerParameters.getServiceSocket(ServerParameters.java:67)
at com.android.jack.server.JackHttpServer.start(JackHttpServer.java:605)
2），需要同时修改 ~/.jack-server/config.properties 中的端口号，方才有效，可以在别的用户启动了jack server的情况再启动另一个jack server，这样就可以实现多用户同时编译，亲测有效：
#Tue Sep 13 17:44:41 CST 2016
jack.server.max-jars-size=104857600
jack.server.max-service=4
jack.server.service.port=8076
jack.server.max-service.by-mem=1\=2147483648\:2\=3221225472\:3\=4294967296
jack.server.admin.port=8077
jack.server.config.version=2
jack.server.time-out=7200 (修改上面红色这2行，比如改为8086，8087等)
总结一下解决方案就是：
同时修改$HOME/.jack-settings和$HOME/.jack-server/config.properties中的端口号（比如都改为8086/8087），方可支持多用户同时编译.
注：有的可能没有config.properties文件，则需要新建一个config.properties文件
之后使用命令重新启动jack
jack-admin stop-server
jack-admin start-server
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