I looked and stepped through the code. All of the existing Realms are initialized at startup. The only way you will get the error message you saw is when there is no property for the user name column in domain.xml
It's an interesting problem. Can you give more details:
Was it a new realm or you are changing an existing one?
What did you type in for user name column?
Is the problem reproducible?
Does a server restart fix the problem (i.e. does the realm work)?
[Message sent by forum member 'bnevins' (bnevins)]
http://forums.java.net/jive/thread.jspa?messageID=237747