public Collection<User> getUsers(final int startIndex, final int numResults) {
        return provider.getUsers(startIndex, numResults);
    }
Returns an unmodifiable Collection of all users starting at {@code startIndex}
with the given number of results. This is useful to support pagination in a GUI
where you may only want to display a certain number of results per page. It is
possible that the number of results returned will be less than that specified
by {@code numResults} if {@code numResults} is greater than the number of
records left to display.

@param startIndex the beginning index to start the results at.
@param numResults the total number of results to return.
@return a Collection of users in the specified range.
xmppserver/src/main/java/org/jivesoftware/openfire/user/UserManager.java