Could anyone let me know why this error happens. Sonar failed to start after upgrading from 6.7.6 to 7.7
2019.04.08 13:17:04 INFO web[o.s.s.p.ServerPluginRepository] Deploy plugin TIBCO BusinessWorks 6 / 1.0.1 / 0
2019.04.08 13:17:09 WARN web[o.s.c.p.PluginLoader] API compatibility mode is no longer supported. In case of error, plugin TIBCO BusinessWorks 6 [tibcobw6] should package its dependencies.
2019.04.08 13:17:11 INFO web[o.s.s.p.w.MasterServletFilter] Initializing servlet filter org.sonar.server.ws.WebServiceFilter@52a4ef80 [pattern=UrlPattern{inclusions=[/api/system/migrate_db., …], exclusions=[/api/properties, …]}]
2019.04.08 13:17:12 INFO web[o.s.s.a.EmbeddedTomcat] HTTP connector enabled on port 9000
2019.04.08 13:17:18 ERROR web[o.s.s.p.Platform] Background initialization failed. Stopping SonarQube
java.lang.IllegalStateException: Fail to load plugin TIBCO BusinessWorks 6 [tibcobw6]
at org.sonar.server.plugins.ServerExtensionInstaller.installExtensions(ServerExtensionInstaller.java:82)
at org.sonar.server.platform.platformlevel.PlatformLevel4.start(PlatformLevel4.java:571)
at org.sonar.server.platform.Platform.start(Platform.java:211)
at org.sonar.server.platform.Platform.startLevel34Containers(Platform.java:185)
at org.sonar.server.platform.Platform.access$500(Platform.java:46)
at org.sonar.server.platform.Platform$1.lambda$doRun$0(Platform.java:119)
at org.sonar.server.platform.Platform$AutoStarterRunnable.runIfNotAborted(Platform.java:371)
at org.sonar.server.platform.Platform$1.doRun(Platform.java:119)
at org.sonar.server.platform.Platform$AutoStarterRunnable.run(Platform.java:355)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NoClassDefFoundError: com/google/common/collect/ImmutableList
at com.tibco.businessworks6.sonar.plugin.BusinessWorksPlugin.getExtensions(BusinessWorksPlugin.java:19)
at org.sonar.api.SonarPlugin.define(SonarPlugin.java:51)
at org.sonar.server.plugins.ServerExtensionInstaller.installExtensions(ServerExtensionInstaller.java:72)
… 9 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.google.common.collect.ImmutableList
at org.sonar.classloader.ParentFirstStrategy.loadClass(ParentFirstStrategy.java:39)
at org.sonar.classloader.ClassRealm.loadClass(ClassRealm.java:87)
at org.sonar.classloader.ClassRealm.loadClass(ClassRealm.java:76)
… 12 common frames omitted
2019.04.08 13:17:18 INFO web[o.s.p.StopWatcher] Stopping process