package

com.atlassian.jira.mail.threading

Classes

EmailHeaderBuilders Responsible for holding the builders used to create the headers inserted into JIRA's notification emails. 
EmailHeaderBuilders.InReplyToHeaderBuilder

Responsible for building the string value for the In-Reply-To header included in JIRA's email notifications. 

EmailHeaderBuilders.MessageIdBuilder Responsible for building the Message-Id string values to be included in JIRA's issue email notifications.