com.atlassian.jira.issue.link
Interfaces 
IssueLinkCreator
IssueLinkManager
IssueLinkTypeDestroyer
IssueLinkTypeManager
Classes 
DefaultIssueLinkCreator
DefaultIssueLinkManager
DefaultIssueLinkTypeManager
IssueLink
IssueLinkType
IssueLinkTypeDestroyerImpl
LinkCollection
SequenceIssueLinkComparator