Slack plugin doesn't post notifications on slack channel starting confluence version 10.x

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    • 1
    • Severity 3 - Minor

      Issue Summary

      Slack notification is not getting triggered on slack channel when a blog post is created OR a normal page is updated or created.

      Steps to Reproduce

      • Install Confluence version 10.x
      • Install "Slack for Confluence Data Center (official)" plugin
      • Create a Slack Workspace by following the below steps
      • Create a new workspace in Slack (Click Atlassian icon > Add a workspace > Create a new workspace
      • It will redirect you to browser where you have to provide email id and create a workspace
      • Then come to Confluence > Slack integration > Go to slack
      • It will take you to another browser where you can Add to Slack
      • Then you get the page similar to the one in KB where we can enter Base URL
      • Copy the Slack credentials for safety sake and submit
      • Open Confluence administration page and got to "Slack integration"
      • Paste the credentials copied slack integration screen
      • Select a space, then select slack channel and the check all the options and then click done.
      • Create confluence blog page and you should not get any notification in slack.
      • Check the atlassian-confluence.log for exception.
      • For full stack trace, please enable DEBUG logging for com.atlassian.plugins.slack and com.atlassian.confluence.plugins.slack

      Expected Results

      Notification should reach to slack when a page is created or updated OR a blog post is created

      Actual Results

      The below exception is thrown in the atlassian-confluence.log. file:

      2026-05-14 06:35:55,569 WARN [slack-client:thread-4] [slack.api.descriptor.SlackNotificationDescriptor] logThrowable Unable to access module for descriptor 'com.atlassian.confluence.plugins.confluence-slack-server-integration-plugin:slack-space-context' of class 'com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor' because of 'io.atlassian.util.concurrent.LazyReference$InitializationException - java.lang.ClassCastException: class com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext cannot be cast to class com.atlassian.plugins.slack.api.notification.SlackNotification (com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext and com.atlassian.plugins.slack.api.notification.SlackNotification are in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @3221ff21)'.  Continuing...
2026-05-14 06:35:55,569 DEBUG [slack-client:thread-4] [slack.api.descriptor.SlackNotificationDescriptor] logThrowable Unable to access module for descriptor 'com.atlassian.confluence.plugins.confluence-slack-server-integration-plugin:slack-space-context' of class 'com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor' because of 'io.atlassian.util.concurrent.LazyReference$InitializationException - java.lang.ClassCastException: class com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext cannot be cast to class com.atlassian.plugins.slack.api.notification.SlackNotification (com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext and com.atlassian.plugins.slack.api.notification.SlackNotification are in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @3221ff21)'.  Continuing...
io.atlassian.util.concurrent.LazyReference$InitializationException: java.lang.ClassCastException: class com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext cannot be cast to class com.atlassian.plugins.slack.api.notification.SlackNotification (com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext and com.atlassian.plugins.slack.api.notification.SlackNotification are in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @3221ff21)
	at io.atlassian.util.concurrent.LazyReference.getInterruptibly(LazyReference.java:156)
	at io.atlassian.util.concurrent.LazyReference.get(LazyReference.java:116)
	at io.atlassian.util.concurrent.ResettableLazyReference.get(ResettableLazyReference.java:95)
	at com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor.getModule(SlackNotificationDescriptor.java:67)
	at com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor.getModule(SlackNotificationDescriptor.java:11)
	at com.atlassian.ozymandias.SafePluginPointAccess.visitPluginPointImpl(SafePluginPointAccess.java:312)
	at com.atlassian.ozymandias.SafePluginPointAccess.descriptors(SafePluginPointAccess.java:213)
	at com.atlassian.ozymandias.SafePluginPointAccess.forType(SafePluginPointAccess.java:107)
	at com.atlassian.plugins.slack.api.descriptor.DefaultNotificationTypeService.getNotificationsForEvent(DefaultNotificationTypeService.java:91)
	at com.atlassian.confluence.plugins.slack.spacetochannel.service.SpaceToChannelNotificationService.lambda$slackNotifications$1(SpaceToChannelNotificationService.java:61)
	at com.atlassian.plugins.slack.util.AsyncExecutor.lambda$run$0(AsyncExecutor.java:36)
	at com.atlassian.sal.core.transaction.HostContextTransactionTemplate$1.doInTransaction(HostContextTransactionTemplate.java:21)
	at com.atlassian.sal.spring.component.SpringHostContextAccessor.lambda$doInTransaction$0(SpringHostContextAccessor.java:72)
	at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
	at com.atlassian.sal.spring.component.SpringHostContextAccessor.doInTransaction(SpringHostContextAccessor.java:70)
	at com.atlassian.sal.core.transaction.HostContextTransactionTemplate.execute(HostContextTransactionTemplate.java:18)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at com.atlassian.plugin.util.ContextClassLoaderSettingInvocationHandler.invoke(ContextClassLoaderSettingInvocationHandler.java:26)
	at jdk.proxy3/jdk.proxy3.$Proxy395.execute(Unknown Source)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:360)
	at org.eclipse.gemini.blueprint.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:56)
	at org.eclipse.gemini.blueprint.service.importer.support.internal.aop.ServiceInvoker.invoke(ServiceInvoker.java:60)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:137)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:124)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.eclipse.gemini.blueprint.service.util.internal.aop.ServiceTCCLInterceptor.invokeUnprivileged(ServiceTCCLInterceptor.java:70)
	at org.eclipse.gemini.blueprint.service.util.internal.aop.ServiceTCCLInterceptor.invoke(ServiceTCCLInterceptor.java:53)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.eclipse.gemini.blueprint.service.importer.support.LocalBundleContextAdvice.invoke(LocalBundleContextAdvice.java:57)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:137)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:124)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:223)
	at jdk.proxy244/jdk.proxy244.$Proxy3476.execute(Unknown Source)
	at com.atlassian.plugins.slack.util.AsyncExecutor.lambda$run$1(AsyncExecutor.java:32)
	at com.atlassian.sal.core.executor.ThreadLocalDelegateRunnable.run(ThreadLocalDelegateRunnable.java:34)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassCastException: class com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext cannot be cast to class com.atlassian.plugins.slack.api.notification.SlackNotification (com.atlassian.confluence.plugins.slack.spacetochannel.notifications.SpaceNotificationContext and com.atlassian.plugins.slack.api.notification.SlackNotification are in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @3221ff21)
	at com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor.createModule(SlackNotificationDescriptor.java:71)
	at com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor$1.create(SlackNotificationDescriptor.java:21)
	at com.atlassian.plugins.slack.api.descriptor.SlackNotificationDescriptor$1.create(SlackNotificationDescriptor.java:18)
	at io.atlassian.util.concurrent.ResettableLazyReference$InternalReference.create(ResettableLazyReference.java:185)
	at io.atlassian.util.concurrent.LazyReference$Sync.run(LazyReference.java:332)
	at io.atlassian.util.concurrent.LazyReference.getInterruptibly(LazyReference.java:150)
	... 45 more

      Resolution

      This bug can be resolved by upgrading the Slack for Confluence Data Center app to 5.0.2 or higher.

              Assignee:
              Przemysław Grabarek
              Reporter:
              Suhel Mohammed
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              0 Vote for this issue
              Watchers:
              3 Start watching this issue

                Created:
                Updated:
                Resolved: