Input to jasper is in JSON format and the data is sent via jsonQLDataSource.
We are using jasperSoft Studio 7.0.1 application to create jrxml files with latest jasper libraries 7.0.1. We are using compiled .jasper files in code so no runtime compilation time is there. RAM is >2GB in local and >8GB on server. Used timer to log data in log files and only below method is taking time. We require the data to finish printing in 4 to 6 seconds or less but its taking 12 to 15 seconds or more which is a lot of wait time for online application. PDF generated is of min 3 pages and max is of 8 pages containing yes no questions and applicant and family details. the jrxml reports we are using contains min 20 fields in 1 report and we have total 100 subreports not necessarily all will be used at a time in 1 pdf (Min 7 files used a time).

JasperPrint jasperprint = JasperFillManager.fillReport(jasperReport, parameters,datasource);

Instead of json, have tried using sql query in jrxml but it takes time during the first hit after every server restart. So what else could be done if i want to proceed with json data?