The class com.atlassian.bamboo.event.ResultLabelEvent takes a com.atlassian.user.User in the constructor.

However, the class members only store the :

private final String username;

with a getUsername() method.

With this setup the ResultLabelEvent essentially drops the other User-related fields passed to the constructor. If you are writing plugins and write a Listener that catches the ResultLabelEvent it would be REALLY useful to get the other fields in the User object other than just the Username without having to inject a user manager and re-lookup the User object using the username.

I would vote for a private member :

private final User user;

with a getter of :

public User getUser(){}

This would allow the subclasses ResultLabelAddedEvent and ResultLabelRemovedEvent access to the User object instead of JUST the Username String.