Summary

Team Calendars only imports .ics files that respects the RFC-2445. However, the Team Calendars plugin expects that the end date exists for every event, which is not actually mandatory according to the mentioned RFC:

2. A calendar entry with a "DTSTART" property but no "DTEND"
property does not take up any time. It is intended to represent
an event that is associated with a given calendar date and time
of day, such as an anniversary. Since the event does not take up
any time, it MUST NOT be used to record busy time no matter what
the value for the "TRANSP" property.

Steps to Reproduce

1. Install a Team Calendars in your Confluence
2. Import a Calendar using the ConfluenceTeamCalendars_webcal.ics file attached to this report.

Expected Results

• The Calendars is imported as expected.

Actual Results

• The below exception is thrown in the atlassian-confluence.log file and the Calendar is not imported:

  2016-10-24 15:30:05,210 ERROR [ajp-nio-8001-exec-6] [extra.calendar3.xwork.ImportSubCalendarAction] execute Unable to import events of type other
   -- referer: http://quicksilver/confluence/calendar/mycalendar.action | url: /confluence/plugins/calendar/importsubcalendar.action | traceId: cfae990fa67f73ba | userName: admin | action: importsubcalendar
  java.lang.NullPointerException
  	at com.atlassian.confluence.extra.calendar3.DefaultActiveObjectsServiceWrapper.createEventEntity(DefaultActiveObjectsServiceWrapper.java:93)
  	at com.atlassian.confluence.extra.calendar3.DefaultActiveObjectsServiceWrapper.createEventEntity(DefaultActiveObjectsServiceWrapper.java:77)
  	at com.atlassian.confluence.extra.calendar3.calendarstore.AbstractCalendarDataStore.setSubCalendarContent(AbstractCalendarDataStore.java:1114)
  	at com.atlassian.confluence.extra.calendar3.calendarstore.AbstractPeopleHandlingSubCalendarDataStore.setSubCalendarContent(AbstractPeopleHandlingSubCalendarDataStore.java:124)
  	at com.atlassian.confluence.extra.calendar3.calendarstore.SanboxSubCalendarDataStoreCachingDecorator.setSubCalendarContent(SanboxSubCalendarDataStoreCachingDecorator.java:149)
  	at com.atlassian.confluence.extra.calendar3.calendarstore.DelegatingCalendarDataStore.setSubCalendarContent(DelegatingCalendarDataStore.java:234)
  	at com.atlassian.confluence.extra.calendar3.DefaultCalendarManager.setSubCalendarContent(DefaultCalendarManager.java:1808)
  	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  	at java.lang.reflect.Method.invoke(Method.java:483)
  	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
  	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
  	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
  	at com.atlassian.plugins.spring.interceptor.plugin.ExportableInterceptorAdapter$WrappedMethodInvocation.proceed(ExportableInterceptorAdapter.java:53)
  	at com.atlassian.plugins.spring.interceptor.spi.SpringInterceptorAdapter$SpringMethodInvocationAdapter.proceed(SpringInterceptorAdapter.java:50)
  	at com.atlassian.spring.interceptors.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:16)
  	at com.atlassian.plugins.spring.interceptor.spi.SpringInterceptorAdapter.invoke(SpringInterceptorAdapter.java:23)
  	at sun.reflect.GeneratedMethodAccessor1098.invoke(Unknown Source)
  	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  	at java.lang.reflect.Method.invoke(Method.java:483)
  	at com.atlassian.plugin.util.ContextClassLoaderSettingInvocationHandler.invoke(ContextClassLoaderSettingInvocationHandler.java:26)
  	at com.sun.proxy.$Proxy287.invoke(Unknown Source)
  	at com.atlassian.plugins.spring.interceptor.plugin.ExportableInterceptorAdapter.invoke(ExportableInterceptorAdapter.java:26)
  	at sun.reflect.GeneratedMethodAccessor1103.invoke(Unknown Source)
  	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  	at java.lang.reflect.Method.invoke(Method.java:483)
  

Notes

• The code for DefaultActiveObjectsServiceWrapper.java:93 is:

  Date endDate = endDateProperty.getDate();
  

Workaround

• Remove the events that do not have DTEND defined, or add a DTEND line for the events in those .ics file.