Since Jasper is an independednt open source to generate the reports in xml,html,csv,pdf and other formats. you can use it from insisde your java classes to generate the report. Its preety easy if you have some tools ike jasper assistant.
Check following links on how to use Jasper reports In nut shell you should write(design) the jrxml files and the then call the jasper API with your java Objects list which you want to print and some parameters. your reports will be generated using api.