The current version of ActivityTimeline application for Jira Server/Data Center supports Jira Server/DC versions that run on Java 8 (including the latest Java 8 security fixes).
The easiest way to get ActivityTimeline app running is to switch Jira to Java 8.
If Jira Server/DC must run on Java 11 then additional configuration of ActivityTimeline is required to work properly.
Configuration Steps
Install Java 8 on the server where Jira is running.
Open <JIRA_HOME>/plugins/activitytimeline/config/at.properties file for editing. <JIRA_HOME> is usually /var/atlassian/application-data/jira on Linux servers.
Add the following line into that file:
at.java_home.path=JAVA8_EXECUTABLE_PATH
where JAVA8_EXECUTABLE_PATH is full path to installed Java 8 executable file. Examples:
/usr/lib/jvm/jre-1.8.0-openjdk.x86_64/bin/java
/usr/lib/jvm/jre-1.8.0/bin/java
C:\\Program Files\\Java\\jre8\bin\\java.exe
Please note that each back-slash should be doubled for Windows OS based server.
Save at.properties file.
Open a troubleshooting page at the following link and click Restart (or Start) service button: https://<JIRA_HOME_URL>/plugins/servlet/activitytimelineconfig/configuration
This should tell ActivityTimeline to use a different version of Java that for Jira.
In this case, Jira will stay on Java 11 while ActivityTimeline will utilize Java 8.
In case you are not sure about the reasons, please make sure to contact our Support Team