UnreachableBrowserException由以下引起：java.lang.NullPointer

我使用的是Selenium 3.4.0,Java 1.8和Firefox 54.0.1(64位).当我尝试打开与Firefox的链接时,我得到一个空指针异常.当我使用Selenium / Python它工作正常,但我正在尝试从这个大师99页面运行代码( https://www.guru99.com/first-webdriver-script.html).I已经搜索,看看是否有其他人有这个问题,但我找不到任何解决方案.我得到以下输出：

1501246654252   addons.manager  DEBUG   Application has been upgraded
1501246654291   addons.manager  DEBUG   Loaded provider scope for resource://gre/modules/addons/XPIProvider.jsm: ["XPIProvider"]
1501246654293   addons.manager  DEBUG   Loaded provider scope for resource://gre/modules/LightweightThemeManager.jsm: ["LightweightThemeManager"]
1501246654297   addons.manager  DEBUG   Loaded provider scope for resource://gre/modules/addons/GMPProvider.jsm
1501246654299   addons.manager  DEBUG   Loaded provider scope for resource://gre/modules/addons/PluginProvider.jsm
1501246654299   addons.manager  DEBUG   Starting provider: XPIProvider
1501246654300   addons.xpi  DEBUG   startup
1501246654301   addons.xpi  INFO    Mapping fxdriver@googlecode.com to C:UsersCHRISG~1AppDataLocalTempanonymous8191426632770324153webdriver-profileextensionsfxdriver@googlecode.com
1501246654301   addons.xpi  DEBUG   Ignoring file entry whose name is not a valid add-on ID: C:UsersCHRISG~1AppDataLocalTempanonymous8191426632770324153webdriver-profileextensionswebdriver-staging
1501246654301   addons.xpi  INFO    Removing all system add-on upgrades.
1501246654301   addons.xpi  INFO    SystemAddonInstallLocation directory is missing
1501246654302   addons.xpi  INFO    Mapping aushelper@mozilla.org to C:Program FilesMozilla Firefoxbrowserfeaturesaushelper@mozilla.org.xpi
1501246654303   addons.xpi  INFO    Mapping e10srollout@mozilla.org to C:Program FilesMozilla Firefoxbrowserfeaturese10srollout@mozilla.org.xpi
1501246654303   addons.xpi  INFO    Mapping firefox@getpocket.com to C:Program FilesMozilla Firefoxbrowserfeaturesfirefox@getpocket.com.xpi
1501246654303   addons.xpi  INFO    Mapping screenshots@mozilla.org to C:Program FilesMozilla Firefoxbrowserfeaturesscreenshots@mozilla.org.xpi
1501246654304   addons.xpi  INFO    Mapping webcompat@mozilla.org to C:Program FilesMozilla Firefoxbrowserfeatureswebcompat@mozilla.org.xpi
1501246654305   addons.xpi  INFO    Mapping {972ce4c6-7e08-4474-a285-3208198ce6fd} to C:Program FilesMozilla Firefoxbrowserextensions{972ce4c6-7e08-4474-a285-3208198ce6fd}.xpi
1501246654305   addons.xpi  DEBUG   Skipping unavailable install location app-system-share
1501246654305   addons.xpi  DEBUG   Skipping unavailable install location app-system-local
1501246654306   addons.xpi  DEBUG   checkForChanges
1501246654306   addons.xpi  INFO    SystemAddonInstallLocation directory is missing
1501246654307   addons.xpi  DEBUG   Loaded add-on state from prefs: {}
1501246654308   addons.xpi  DEBUG   New add-on fxdriver@googlecode.com in app-profile
1501246654308   addons.xpi  DEBUG   getModTime: Recursive scan of fxdriver@googlecode.com
1501246654313   addons.xpi  DEBUG   New add-on aushelper@mozilla.org in app-system-defaults
1501246654313   addons.xpi  DEBUG   getModTime: Recursive scan of aushelper@mozilla.org
1501246654314   addons.xpi  DEBUG   New add-on e10srollout@mozilla.org in app-system-defaults
1501246654315   addons.xpi  DEBUG   getModTime: Recursive scan of e10srollout@mozilla.org
1501246654315   addons.xpi  DEBUG   New add-on firefox@getpocket.com in app-system-defaults
1501246654315   addons.xpi  DEBUG   getModTime: Recursive scan of firefox@getpocket.com
1501246654315   addons.xpi  DEBUG   New add-on screenshots@mozilla.org in app-system-defaults
1501246654316   addons.xpi  DEBUG   getModTime: Recursive scan of screenshots@mozilla.org
1501246654316   addons.xpi  DEBUG   New add-on webcompat@mozilla.org in app-system-defaults
1501246654316   addons.xpi  DEBUG   getModTime: Recursive scan of webcompat@mozilla.org
1501246654317   addons.xpi  DEBUG   New add-on {972ce4c6-7e08-4474-a285-3208198ce6fd} in app-global
1501246654317   addons.xpi  DEBUG   getModTime: Recursive scan of {972ce4c6-7e08-4474-a285-3208198ce6fd}
1501246654317   addons.xpi  DEBUG   getInstallState changed: true,state: {"app-profile":{"fxdriver@googlecode.com":{"d":"C:UsersCHRISG~1AppDataLocalTempanonymous8191426632770324153webdriver-profileextensionsfxdriver@googlecode.com","st":1501246654037,"mt":1501246653985}},"app-system-defaults":{"aushelper@mozilla.org":{"d":"C:Program FilesMozilla Firefoxbrowserfeaturesaushelper@mozilla.org.xpi","st":1498667065000},"e10srollout@mozilla.org":{"d":"C:Program FilesMozilla Firefoxbrowserfeaturese10srollout@mozilla.org.xpi","firefox@getpocket.com":{"d":"C:Program FilesMozilla Firefoxbrowserfeaturesfirefox@getpocket.com.xpi","st":1498667066000},"screenshots@mozilla.org":{"d":"C:Program FilesMozilla Firefoxbrowserfeaturesscreenshots@mozilla.org.xpi","st":1498667067000},"webcompat@mozilla.org":{"d":"C:Program FilesMozilla Firefoxbrowserfeatureswebcompat@mozilla.org.xpi","st":1498667066000}},"app-global":{"{972ce4c6-7e08-4474-a285-3208198ce6fd}":{"d":"C:Program FilesMozilla Firefoxbrowserextensions{972ce4c6-7e08-4474-a285-3208198ce6fd}.xpi","st":1498667065000}}}
1501246654324   addons.xpi-utils    DEBUG   Opening XPI database C:UsersCHRISG~1AppDataLocalTempanonymous8191426632770324153webdriver-profileextensions.json
1501246654326   addons.xpi-utils    DEBUG   New add-on fxdriver@googlecode.com installed in app-profile
*** Blocklist::_loadBlocklistFromFile: blocklist is disabled
1501246654340   addons.xpi  WARN    Add-on fxdriver@googlecode.com is not correctly signed.
1501246654340   addons.xpi  WARN    Add-on fxdriver@googlecode.com is not correctly signed.
1501246654343   DeferredSave.extensions.json    DEBUG   Save changes
1501246654343   addons.xpi-utils    DEBUG   New add-on aushelper@mozilla.org installed in app-system-defaults
1501246654346   DeferredSave.extensions.json    DEBUG   Starting timer
1501246654349   DeferredSave.extensions.json    DEBUG   Save changes
1501246654349   addons.xpi-utils    DEBUG   New add-on e10srollout@mozilla.org installed in app-system-defaults
1501246654354   DeferredSave.extensions.json    DEBUG   Save changes
1501246654355   addons.xpi-utils    DEBUG   New add-on firefox@getpocket.com installed in app-system-defaults
1501246654359   DeferredSave.extensions.json    DEBUG   Save changes
1501246654359   addons.xpi-utils    DEBUG   New add-on screenshots@mozilla.org installed in app-system-defaults
1501246654365   DeferredSave.extensions.json    DEBUG   Save changes
1501246654365   addons.xpi-utils    DEBUG   New add-on webcompat@mozilla.org installed in app-system-defaults
1501246654369   DeferredSave.extensions.json    DEBUG   Save changes
1501246654370   addons.xpi-utils    DEBUG   New add-on {972ce4c6-7e08-4474-a285-3208198ce6fd} installed in app-global
1501246654373   DeferredSave.extensions.json    DEBUG   Starting write
1501246654379   DeferredSave.extensions.json    DEBUG   Save changes
1501246654380   DeferredSave.extensions.json    DEBUG   Data changed while write in progress
1501246654380   addons.manager  DEBUG   Registering startup change 'installed' for fxdriver@googlecode.com
1501246654380   addons.xpi-utils    DEBUG   Make addon app-profile:fxdriver@googlecode.com visible
1501246654381   DeferredSave.extensions.json    DEBUG   Save changes
1501246654381   addons.manager  DEBUG   Registering startup change 'installed' for aushelper@mozilla.org
1501246654390   addons.xpi  DEBUG   Loading bootstrap scope from C:Program FilesMozilla Firefoxbrowserfeaturesaushelper@mozilla.org.xpi
1501246654394   addons.xpi  DEBUG   Calling bootstrap method install on aushelper@mozilla.org version 2.0
1501246654395   addons.xpi-utils    DEBUG   Make addon app-system-defaults:aushelper@mozilla.org visible
1501246654395   DeferredSave.extensions.json    DEBUG   Save changes
1501246654395   addons.manager  DEBUG   Registering startup change 'installed' for e10srollout@mozilla.org
1501246654396   addons.xpi  DEBUG   Loading bootstrap scope from C:Program FilesMozilla Firefoxbrowserfeaturese10srollout@mozilla.org.xpi
1501246654399   addons.xpi  DEBUG   Calling bootstrap method install on e10srollout@mozilla.org version 1.50
1501246654400   addons.xpi-utils    DEBUG   Make addon app-system-defaults:e10srollout@mozilla.org visible
1501246654400   DeferredSave.extensions.json    DEBUG   Save changes
1501246654400   addons.manager  DEBUG   Registering startup change 'installed' for firefox@getpocket.com
1501246654401   addons.xpi  DEBUG   Loading bootstrap scope from C:Program FilesMozilla Firefoxbrowserfeaturesfirefox@getpocket.com.xpi
1501246654405   addons.xpi  DEBUG   Calling bootstrap method install on firefox@getpocket.com version 1.0.5
1501246654405   addons.xpi-utils    DEBUG   Make addon app-system-defaults:firefox@getpocket.com visible
1501246654406   DeferredSave.extensions.json    DEBUG   Save changes
1501246654406   addons.manager  DEBUG   Registering startup change 'installed' for screenshots@mozilla.org
1501246654407   addons.xpi  DEBUG   Loading bootstrap scope from C:Program FilesMozilla Firefoxbrowserfeaturesscreenshots@mozilla.org.xpi
1501246654410   addons.xpi  DEBUG   Calling bootstrap method install on screenshots@mozilla.org version 6.6.0
1501246654410   addons.xpi-utils    DEBUG   Make addon app-system-defaults:screenshots@mozilla.org visible
1501246654410   DeferredSave.extensions.json    DEBUG   Save changes
1501246654410   addons.manager  DEBUG   Registering startup change 'installed' for webcompat@mozilla.org
1501246654411   addons.xpi  DEBUG   Loading bootstrap scope from C:Program FilesMozilla Firefoxbrowserfeatureswebcompat@mozilla.org.xpi
1501246654413   addons.xpi  DEBUG   Calling bootstrap method install on webcompat@mozilla.org version 1.1
1501246654413   addons.xpi-utils    DEBUG   Make addon app-system-defaults:webcompat@mozilla.org visible
1501246654413   DeferredSave.extensions.json    DEBUG   Save changes
1501246654414   addons.xpi-utils    DEBUG   Make addon app-global:{972ce4c6-7e08-4474-a285-3208198ce6fd} visible
1501246654414   DeferredSave.extensions.json    DEBUG   Save changes
1501246654414   addons.xpi  DEBUG   Updating XPIState for {"id":"fxdriver@googlecode.com","syncGUID":"{284a66e3-05a6-4d03-b43d-a92a5f93e2f7}","location":"app-profile","version":"3.4.0","type":"extension","internalName":null,"updateURL":null,"updateKey":null,"optionsURL":null,"optionsType":null,"aboutURL":null,"icons":{},"iconURL":null,"icon64URL":null,"defaultLocale":{"name":"Firefox WebDriver","description":"WebDriver implementation for Firefox","creator":"Simon Stewart","homepageURL":null},"visible":true,"active":false,"userDisabled":false,"appDisabled":true,"descriptor":"C:UsersCHRISG~1AppDataLocalTempanonymous8191426632770324153webdriver-profileextensionsfxdriver@googlecode.com","installDate":1501246654037,"updateDate":1501246654037,"applyBackgroundUpdates":1,"bootstrap":false,"skinnable":false,"size":3303362,"sourceURI":null,"releaseNotesURI":null,"softDisabled":false,"foreignInstall":true,"hasBinaryComponents":false,"strictCompatibility":false,"locales":[],"targetApplications":[{"id":"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}","minVersion":"3.0","maxVersion":"48.0"}],"targetPlatforms":[{"os":"Darwin","abi":null},{"os":"SunOS",{"os":"FreeBSD",{"os":"OpenBSD",{"os":"WINNT",{"os":"Linux","abi":null}],"multiprocessCompatible":false,"signedState":0,"seen":true,"dependencies":[],"hasEmbeddedWebExtension":false,"mpcOptedOut":false,"userPermissions":null}
1501246654415   addons.xpi  DEBUG   Updating XPIState for {"id":"aushelper@mozilla.org","syncGUID":"{a337c938-f101-467f-8334-642c2957ef77}","location":"app-system-defaults","version":"2.0","defaultLocale":{"name":"Application Update Service Helper","description":"Sets value(s) in the update url based on custom checks.","creator":null,"active":true,"appDisabled":false,"descriptor":"C:Program FilesMozilla Firefoxbrowserfeaturesaushelper@mozilla.org.xpi","installDate":1498667065000,"updateDate":1498667065000,"bootstrap":true,"size":8488,"foreignInstall":false,"minVersion":"54.0.1","maxVersion":"54.*"}],"targetPlatforms":[],"multiprocessCompatible":true,"userPermissions":null}
1501246654415   addons.xpi  DEBUG   getModTime: Recursive scan of aushelper@mozilla.org
1501246654415   addons.xpi  DEBUG   Updating XPIState for {"id":"e10srollout@mozilla.org","syncGUID":"{253d1e2b-244f-48a3-8215-48fd1ea043b0}","version":"1.50","defaultLocale":{"name":"Multi-process staged rollout","description":"Staged rollout of Firefox multi-process feature.","descriptor":"C:Program FilesMozilla Firefoxbrowserfeaturese10srollout@mozilla.org.xpi","size":12519,"userPermissions":null}
1501246654415   addons.xpi  DEBUG   getModTime: Recursive scan of e10srollout@mozilla.org
1501246654416   addons.xpi  DEBUG   Updating XPIState for {"id":"firefox@getpocket.com","syncGUID":"{82e97246-464d-494a-92d5-df6243a967d5}","version":"1.0.5","defaultLocale":{"name":"Pocket","description":"When you find something you want to view later,put it in Pocket.","descriptor":"C:Program FilesMozilla Firefoxbrowserfeaturesfirefox@getpocket.com.xpi","installDate":1498667066000,"updateDate":1498667066000,"size":913906,"userPermissions":null}
1501246654416   addons.xpi  DEBUG   getModTime: Recursive scan of firefox@getpocket.com
1501246654417   addons.xpi  DEBUG   Updating XPIState for {"id":"screenshots@mozilla.org","syncGUID":"{88407b9c-4ff8-4d68-9615-aa613dbe559f}","version":"6.6.0","defaultLocale":{"name":"Firefox Screenshots","description":null,"homepageURL":"https://pageshot.net/"},"descriptor":"C:Program FilesMozilla Firefoxbrowserfeaturesscreenshots@mozilla.org.xpi","installDate":1498667067000,"updateDate":1498667067000,"size":716271,"minVersion":"51.0a1","maxVersion":"*"}],"userPermissions":null}
1501246654417   addons.xpi  DEBUG   getModTime: Recursive scan of screenshots@mozilla.org
1501246654418   addons.xpi  DEBUG   Updating XPIState for {"id":"webcompat@mozilla.org","syncGUID":"{21466d10-4f5e-4882-9e6b-1d1c096fc15b}","version":"1.1","defaultLocale":{"name":"Web Compat","description":"Urgent post-release fixes for web compatibility.","descriptor":"C:Program FilesMozilla Firefoxbrowserfeatureswebcompat@mozilla.org.xpi","size":9006,"userPermissions":null}
1501246654418   addons.xpi  DEBUG   getModTime: Recursive scan of webcompat@mozilla.org
1501246654419   addons.xpi  DEBUG   Updating XPIState for {"id":"{972ce4c6-7e08-4474-a285-3208198ce6fd}","syncGUID":"{374c68bf-b5ce-4e4f-a6c4-f1532a743336}","location":"app-global","version":"54.0.1","type":"theme","internalName":"classic/1.0","iconURL":"chrome://browser/content/default-theme-icon.svg","defaultLocale":{"name":"Default","description":"The default theme.","creator":"Mozilla","homepageURL":null,"contributors":["Mozilla Contributors"]},"descriptor":"C:Program FilesMozilla Firefoxbrowserextensions{972ce4c6-7e08-4474-a285-3208198ce6fd}.xpi","skinnable":true,"size":8207,"strictCompatibility":true,"maxVersion":"54.0.1"}],"userPermissions":null}
1501246654420   addons.xpi  DEBUG   getModTime: Recursive scan of {972ce4c6-7e08-4474-a285-3208198ce6fd}
1501246654444   DeferredSave.extensions.json    DEBUG   Save changes
1501246654444   addons.xpi  DEBUG   Updating database with changes to installed add-ons
1501246654444   addons.xpi-utils    DEBUG   Updating add-on states
1501246654445   addons.xpi-utils    DEBUG   Writing add-ons list
1501246654452   addons.xpi  DEBUG   Registering manifest for C:Program FilesMozilla Firefoxbrowserfeaturesaushelper@mozilla.org.xpi
1501246654452   addons.xpi  DEBUG   Calling bootstrap method startup on aushelper@mozilla.org version 2.0
1501246654453   addons.xpi  DEBUG   Registering manifest for C:Program FilesMozilla Firefoxbrowserfeaturese10srollout@mozilla.org.xpi
1501246654454   addons.xpi  DEBUG   Calling bootstrap method startup on e10srollout@mozilla.org version 1.50
1501246654455   addons.xpi  DEBUG   Registering manifest for C:Program FilesMozilla Firefoxbrowserfeaturesfirefox@getpocket.com.xpi
1501246654456   addons.xpi  DEBUG   Calling bootstrap method startup on firefox@getpocket.com version 1.0.5
1501246654456   addons.xpi  DEBUG   Registering manifest for C:Program FilesMozilla Firefoxbrowserfeaturesscreenshots@mozilla.org.xpi
1501246654457   addons.xpi  DEBUG   Calling bootstrap method startup on screenshots@mozilla.org version 6.6.0
1501246654457   addons.xpi  DEBUG   Registering manifest for C:Program FilesMozilla Firefoxbrowserfeatureswebcompat@mozilla.org.xpi
1501246654458   addons.xpi  DEBUG   Calling bootstrap method startup on webcompat@mozilla.org version 1.1
1501246654461   addons.manager  DEBUG   Registering shutdown blocker for XPIProvider
1501246654462   addons.manager  DEBUG   Provider finished startup: XPIProvider
1501246654462   addons.manager  DEBUG   Starting provider: LightweightThemeManager
1501246654462   addons.manager  DEBUG   Registering shutdown blocker for LightweightThemeManager
1501246654462   addons.manager  DEBUG   Provider finished startup: LightweightThemeManager
1501246654462   addons.manager  DEBUG   Starting provider: GMPProvider
1501246654467   addons.manager  DEBUG   Registering shutdown blocker for GMPProvider
1501246654467   addons.manager  DEBUG   Provider finished startup: GMPProvider
1501246654467   addons.manager  DEBUG   Starting provider: PluginProvider
1501246654467   addons.manager  DEBUG   Registering shutdown blocker for PluginProvider
1501246654467   addons.manager  DEBUG   Provider finished startup: PluginProvider
1501246654468   addons.manager  DEBUG   Completed startup sequence
1501246654778   addons.manager  DEBUG   Starting provider: <unnamed-provider>
1501246654778   addons.manager  DEBUG   Registering shutdown blocker for <unnamed-provider>
1501246654779   addons.manager  DEBUG   Provider finished startup: <unnamed-provider>
1501246654937   DeferredSave.extensions.json    DEBUG   Write succeeded
1501246654937   addons.xpi-utils    DEBUG   XPI Database saved,setting schema version preference to 19
1501246654937   DeferredSave.extensions.json    DEBUG   Starting timer
1501246654951   addons.repository   DEBUG   No addons.json found.
1501246654951   DeferredSave.addons.json    DEBUG   Save changes
1501246654954   DeferredSave.addons.json    DEBUG   Starting timer
1501246654976   addons.manager  DEBUG   Starting provider: PreviousExperimentProvider
1501246654976   addons.manager  DEBUG   Registering shutdown blocker for PreviousExperimentProvider
1501246654976   addons.manager  DEBUG   Provider finished startup: PreviousExperimentProvider
1501246654979   DeferredSave.extensions.json    DEBUG   Starting write
1501246655004   DeferredSave.addons.json    DEBUG   Starting write
1501246655006   DeferredSave.extensions.json    DEBUG   Write succeeded
1501246655021   DeferredSave.addons.json    DEBUG   Write succeeded
[GPU 7220] WARNING: pipe error: 109: file c:/builds/moz2_slave/m-rel-w64-00000000000000000000/build/src/ipc/chromium/src/chrome/common/ipc_channel_win.cc,line 346
Exception in thread "main" org.openqa.selenium.remote.UnreachableBrowserException: Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure.
Build info: version: 'unknown',revision: 'unknown',time: 'unknown'
System info: host: 'CHRIS-PC',ip: '192.xxx.x.xxx',os.name: 'Windows 10',os.arch: 'amd64',os.version: '10.0',java.version: '1.8.0_141'
Driver info: driver.version: FirefoxDriver
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:658)
    at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:250)
    at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:236)
    at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:137)
    at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:191)
    at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:108)
    at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:104)
    at newpackage.MyClass.main(MyClass.java:12)
Caused by: java.lang.NullPointerException
    at org.openqa.selenium.remote.service.DriverService.waitUntilAvailable(DriverService.java:192)
    at org.openqa.selenium.firefox.XpiDriverService.start(XpiDriverService.java:94)
    at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:78)
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:637)
    ... 7 more

System.setProperty("webdriver.firefox.marionette","C:geckodriver.exe");

System.setProperty("webdriver.gecko.driver","C:your_directorygeckodriver.exe");