how to fix sonar issues - resultset is never closed

We have a scenario where we need to build a object with around 250 attributes and pass it via soap web services. Also we need to send a huge collection of this object as an input to the service call. We have not implemented that fully. But we are afraid if this would reduce the speed of transfer objects and kill the heap memory too. Any other suggestions to have a better coding and approach ?

Note : we had alternate approach to have the same in Database instead of web service call. But client wants a web service call for some business need from front end.