It is quite easy to integrate Jira with OpenAM with help from this wiki - Integrate with Atlassian Jira and Confluence.
However, we kept getting the following AbstractMethodError during runtime.
Cause: java.lang.AbstractMethodError: com.sun.identity.provider.seraph.OpenSsoAuthenticator.getUser(Ljava/lang/String;)Ljava/security/Principal;
Upon another round of checking, we realized there is something different between what is stated in the wiki and what we have in our seraph-config.xml.
The wiki assumes the older versions of Jira is using DefaultAuthenticator. However, in our XML properties file, we are seeing JiraSeraphAuthenticator (which extends from DefaultAuthenticator).
What to do next? Change code!
Replace DefaultAuthenticator with JiraSeraphAuthenticator in OpenSsoAuthenticator did the trick!