title: flutter: Gradle build daemon disappeared unexpectedly (it may have been killed or may have crashed)
body: <p>I'm working with flutter in ubuntu 18.04. I can't run my project although <code>flutter doctor</code> is no problem. I stuck in the problem of <code>Gradle daemon</code>. I have tried the method in <a href="https://docs.gradle.org/current/userguide/gradle_daemon.html#sec:disabling_the_daemon" rel="nofollow noreferrer">gradle user guide</a> and other <a href="https://stackoverflow.com/questions/37171043/gradle-build-daemon-disappeared-unexpectedly-it-may-have-been-killed-or-may-hav">questions</a> in SO to add <code>org.gradle.daemon=false</code> in <code>gradle.properties</code>, but the same problem. What's wrong?</p>
  <pre><code>Launching lib/main.dart on M2006C3LC in debug mode...
  The message received from the daemon indicates that the daemon has disappeared.
  Build request sent: Build{id=0846277b-6ded-4171-9a9a-ce34e51b07be, currentDir=/home/byhuang/flutterOpenProject/flutter_init_demo/android}
  Attempting to read last messages from the daemon log...                 
  Daemon pid: 3422                                                        
    log file: /home/byhuang/.gradle/daemon/5.6.2/daemon-3422.out.log      
  ----- Last  20 lines from daemon log file - daemon-3422.out.log -----   
  11:38:04.753 [DEBUG] [org.gradle.launcher.daemon.server.DefaultIncomingConnectionHandler] Starting executing command: Build{id=0846277b-6ded-4171-9a9a-ce34e51b07be, currentDir=/home/byhuang/flutterOpenProject/flutter_init_demo/android} with connection: socket connection from /0:0:0:0:0:0:0:1:41393 to /0:0:0:0:0:0:0:1:46484.
  11:38:04.755 [ERROR] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] Command execution: started DaemonCommandExecution[command = Build{id=0846277b-6ded-4171-9a9a-ce34e51b07be, currentDir=/home/byhuang/flutterOpenProject/flutter_init_demo/android}, connection = DefaultDaemonConnection: socket connection from /0:0:0:0:0:0:0:1:41393 to /0:0:0:0:0:0:0:1:46484] after 0.0 minutes of idle
  11:38:04.756 [INFO] [org.gradle.launcher.daemon.server.DaemonRegistryUpdater] Marking the daemon as busy, address: [f54344e9-fcb9-455f-a518-b1d7af504663 port:41393, addresses:[/0:0:0:0:0:0:0:1%lo, /127.0.0.1]]
  11:38:04.763 [DEBUG] [org.gradle.launcher.daemon.registry.PersistentDaemonRegistry] Marking busy by address: [f54344e9-fcb9-455f-a518-b1d7af504663 port:41393, addresses:[/0:0:0:0:0:0:0:1%lo, /127.0.0.1]]
  11:38:04.790 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Waiting to acquire exclusive lock on daemon addresses registry.
  11:38:04.791 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Lock acquired on daemon addresses registry.
  11:38:04.804 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on daemon addresses registry.
  11:38:04.805 [DEBUG] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] resetting idle timer
  11:38:04.805 [DEBUG] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] daemon is running. Sleeping until state changes.
  11:38:04.810 [INFO] [org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy] Daemon is about to start building Build{id=0846277b-6ded-4171-9a9a-ce34e51b07be, currentDir=/home/byhuang/flutterOpenProject/flutter_init_demo/android}. Dispatching build started information...
  11:38:04.811 [DEBUG] [org.gradle.launcher.daemon.server.SynchronizedDispatchConnection] thread 17: dispatching class org.gradle.launcher.daemon.protocol.BuildStarted
  11:38:04.812 [DEBUG] [org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment] Configuring env variables: {PATH=/home/byhuang/src/FlutterSDK/flutter/bin/cache/dart-sdk/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/byhuang/.pub-cache/bin:~/src/FlutterSDK/flutter/bin, XAUTHORITY=/run/user/1000/gdm/Xauthority, INVOCATION_ID=bb1359976cdb403b93f2e6bd5fa0d6e7, XMODIFIERS=@im=ibus, GDMSESSION=ubuntu, XDG_DATA_DIRS=/usr/share/ubuntu:/usr/local/share:/usr/share:/var/lib/snapd/desktop, TEXTDOMAINDIR=/usr/share/locale/, GTK_IM_MODULE=ibus, DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus,guid=e1b93d29865be954f2c06fce5fe015cb, PUB_HOSTED_URL=https://pub.flutter-io.cn, XDG_CURRENT_DESKTOP=ubuntu:GNOME, JOURNAL_STREAM=9:49578, SSH_AGENT_PID=1797, COLORTERM=truecolor, QT4_IM_MODULE=xim, SESSION_MANAGER=local/byhuang-virtual-machine:@/tmp/.ICE-unix/1702,unix/byhuang-virtual-machine:/tmp/.ICE-unix/1702, USERNAME=byhuang, LOGNAME=byhuang, PWD=/home/byhuang/flutterOpenProject/flutter_init_demo/android, MANAGERPID=1667, IM_CONFIG_PHASE=2, LANGUAGE=zh_CN:zh, LESSOPEN=| /usr/bin/lesspipe %s, SHELL=/bin/bash, OLDPWD=/home/byhuang/flutterOpenProject/flutter_init_demo/android, GNOME_DESKTOP_SESSION_ID=this-is-deprecated, GTK_MODULES=gail:atk-bridge, GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/1c43d352_e494_406b_b4b1_8e1a6bf95400, CLUTTER_IM_MODULE=xim, TEXTDOMAIN=im-config, DBUS_STARTER_ADDRESS=unix:path=/run/user/1000/bus,guid=e1b93d29865be954f2c06fce5fe015cb, FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn, XDG_SESSION_DESKTOP=ubuntu, LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:, SHLVL=2, LESSCLOSE=/usr/bin/lesspipe %s %s, QT_IM_MODULE=xim, JAVA_HOME=/home/byhuang/software/android-studio/jre, TERM=xterm-256color, FLUTTER_ROOT=/home/byhuang/src/FlutterSDK/flutter, XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg, GNOME_TERMINAL_SERVICE=:1.59, LANG=zh_CN.UTF-8, XDG_SESSION_TYPE=x11, XDG_SESSION_ID=4, DISPLAY=:1, FLUTTER_SUPPRESS_ANALYTICS=true, GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1, DESKTOP_SESSION=ubuntu, USER=byhuang, XDG_MENU_PREFIX=gnome-, VTE_VERSION=5202, WINDOWPATH=1, QT_ACCESSIBILITY=1, XDG_SEAT=seat0, SSH_AUTH_SOCK=/run/user/1000/keyring/ssh, FLUTTER_ALREADY_LOCKED=true, GNOME_SHELL_SESSION_MODE=ubuntu, XDG_RUNTIME_DIR=/run/user/1000, XDG_VTNR=1, DBUS_STARTER_BUS_TYPE=session, HOME=/home/byhuang}
  11:38:04.826 [DEBUG] [org.gradle.launcher.daemon.server.exec.LogToClient] About to start relaying all logs to the client via the connection.
  11:38:04.826 [INFO] [org.gradle.launcher.daemon.server.exec.LogToClient] The client will now receive all logging from the daemon (pid: 3422). The daemon log file: /home/byhuang/.gradle/daemon/5.6.2/daemon-3422.out.log
  11:38:04.832 [DEBUG] [org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon] Requesting daemon stop after processing Build{id=0846277b-6ded-4171-9a9a-ce34e51b07be, currentDir=/home/byhuang/flutterOpenProject/flutter_init_demo/android}
  11:38:04.832 [LIFECYCLE] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] Daemon will be stopped at the end of the build stopping after processing
  11:38:04.832 [DEBUG] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] Stop as soon as idle requested. The daemon is busy: true
  11:38:04.835 [DEBUG] [org.gradle.launcher.daemon.server.DaemonStateCoordinator] daemon stop has been requested. Sleeping until state changes.
  11:38:04.835 [DEBUG] [org.gradle.launcher.daemon.server.exec.ExecuteBuild] The daemon has started executing the build.
  11:38:04.839 [DEBUG] [org.gradle.launcher.daemon.server.exec.ExecuteBuild] Executing build with daemon context: DefaultDaemonContext[uid=cbbde454-54e4-47ec-b258-28179c1fddfe,javaHome=/home/byhuang/software/android-studio/jre,daemonRegistryDir=/home/byhuang/.gradle/daemon,pid=3422,idleTimeout=120000,priority=NORMAL,daemonOpts=-Xmx1536M,-Dfile.encoding=UTF-8,-Duser.country=CN,-Duser.language=zh,-Duser.variant]
  ----- End of the daemon log -----                                       
                                                                          
                                                                          
  FAILURE: Build failed with an exception.                                
                                                                          
  * What went wrong:                                                      
  Gradle build daemon disappeared unexpectedly (it may have been killed or may have crashed)
                                                                          
  * Try:                                                                  
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
                                                                          
  * Get more help at https://help.gradle.org                              
  Running Gradle task 'assembleDebug'...                                  
  Running Gradle task 'assembleDebug'... Done                        29.2s
  Exception: Gradle task assembleDebug failed with exit code 1
  
  </code></pre>
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