public static String getPassword(String username) throws UserNotFoundException,
            UnsupportedOperationException {
        return authProvider.getPassword(username.toLowerCase());
    }
Returns the user's password. This method will throw an UnsupportedOperationException
if this operation is not supported by the backend user store.

@param username the username of the user.
@return the user's password.
@throws UserNotFoundException if the given user could not be found.
@throws UnsupportedOperationException if the provider does not
     support the operation (this is an optional operation).
xmppserver/src/main/java/org/jivesoftware/openfire/auth/AuthFactory.java