After JasperReports run againts a database, a .jrprint file is generated. This file contains the executed report, which you can save and view later. It's also possible for the user to save the report in pdf, html or other format, but this is native JasperReport format, from which JasperReport library can export in a supported format.

We have a special editor to open this file, the editor contains a toolbar with actions and tools to zoom the report and export to a supported format, just double click on the .jrprint file it will be opened automatically.