It is dangerous to use this method.
|From class java.lang.Object|
It is dangerous to use this method. In general operation JIRA needs to keep the userName -> key mapping around even if the user is deleted. This is so that it can show something in the UI after the user is deleted.
This method is used by cloud for import where all the users are deleted anyways (see JiraUserServiceImpl).
|key||the key to remove.|