I am new to Jasper Reports. I have designed a report, and I am calling it from a java program to generate the report output in .pdf format, using the following type of statements; jasperReport = JasperCompileManager.compileReport(xmlFileName); jasperPrint = JasperFillManager.fillReport(jasperReport, hashMap, new JRResultSetDataSource(resultSet)); JasperExportManager.exportReportToPdfFile(jasperPrint,pdfFileName); (The hashMap and the resultSet objects are properly set to correct values) When the report specified by (xmlFileName) has no sub-reports, the reports runs successfully, and I get the output in a .pdf file. But when this report has sub-reports, I get a run time error at the statements that fills the main report. (It should be noted that I have put the .jrxml files for the sub-reports in the same directory as the original report, and have defined the path to sub-reports in the main report via property pallete in the iReport designer). Can someone please help me telling what I am doing wrong, and what steps need to be done to resolve the issue?