Error messages when using j_security_check

[Jan Arendtsz <ar...@pacbell.net>]

My application uses form based authentication using the Tomcat JDBC Realm by posting to j_security_check as defined in the servlet specification.  

Everything works fine except when I enter an invalid user id / password combination which results in a redirect to the error page but instead of a specific error (such as invalid username/password), I get a null pointer exception.  Is this a bug?

I would expect the Tomcat implementation to provide specific error messages as follows:
- Invalid User Id and password
- Invalid User Id
- Invalid Password (user id exists)

Any help is appreciated.

Thanks
Jan