Android 源码编译时，经常会遇到jack通信失败问题。
[100% 1/1] 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 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.RELEASE.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/songzhihao/.jack-server"
Communication error with Jack server (77), try 'jack-diagnose' or see Jack server log
Failed to contact Jack server: Problem reading /home/songzhihao/.jack-server/server.pem. Try 'jack-diagnose'
Failed to contact Jack server: Problem reading /home/songzhihao/.jack-server/server.pem. Try 'jack-diagnose'
ninja: build stopped: subcommand failed.
build/core/ninja.mk:148: recipe for target 'ninja_wrapper' failed
make: *** [ninja_wrapper] Error 1
遇到类似的问题，我们首先要去prebuilts/sdk/tools目录下，运行jack-diagnose命令看一下是什么原因，如果是端口号被占用的问题，先不要着急去改jack-server的端口号，首先看一下是什么进程占用了该端口。
netstat -ap | grep port
就可以看到占用这个端口号的进程是哪个了，然后运行
$ kill -9 该进程pid
再次make Android源码即可。
PS：通过netstat查看到占用该端口号的进程是java，怀疑是上一次编译失败退出后，后台启动的java进程并没有退出，一直占用这个这个port导致的，所以kill掉这个java进程就解决了，个人感觉根本原因是因为Android源码编译的异常退出机制，做的不够完善。
