EDIT

in all service methods returning lists or pagers the following statement is being used to check if the query would return any records.

if(numberOfResults > 0) { // no point checking again

this should be replaced by

if(AbstractPagerImpl.hasResultsInRange(numberOfResults, pageNumber, pageSize){ // no point checking again

I added according TODO comments to most of these cases.

The reason for this actually is a bug which did the calculation of hasResultsInRange incorrectly. So I decided that this should be done centrally in static method. The AbtractPagerImpl seems a good place for it since it is anyway planned to implement such functionality into it #691