Dear community, I am using JRSwapFileVirtualizer for large datasets from the Oracle database, reports are filled by SQL query. JasperFillManager.fillReport ends successfully, jasperPrint is created and JRSwapFileVirtualizer is used properly. In the report design, I have got a table dataset, with 8 grouping criteria. When It comes to generating report PDF, I have got a java.lang.OutOfMemoryError: Java heap space: java.lang.OutOfMemoryError: Java heap spacejava.lang.OutOfMemoryError: Java heap space at com.lowagie.text.pdf.ByteBuffer.append_i(Unknown Source) at com.lowagie.text.pdf.ByteBuffer.append(Unknown Source) at com.lowagie.text.pdf.ByteBuffer.formatDouble(Unknown Source) at com.lowagie.text.pdf.ByteBuffer.append(Unknown Source) at com.lowagie.text.pdf.ByteBuffer.append(Unknown Source) at com.lowagie.text.pdf.PdfContentByte.setLineCap(Unknown Source) at net.sf.jasperreports.engine.export.JRPdfExporter.preparePen(JRPdfExporter.java:3147) at net.sf.jasperreports.engine.export.JRPdfExporter.exportBottomPen(JRPdfExporter.java:3038) at net.sf.jasperreports.engine.export.JRPdfExporter.exportBox(JRPdfExporter.java:2891) at net.sf.jasperreports.engine.export.JRPdfExporter.exportFrame(JRPdfExporter.java:3386) at net.sf.jasperreports.engine.export.JRPdfExporter.exportElements(JRPdfExporter.java:1108) at net.sf.jasperreports.engine.export.JRPdfExporter.exportFrame(JRPdfExporter.java:3379) at net.sf.jasperreports.engine.export.JRPdfExporter.exportElements(JRPdfExporter.java:1108) at net.sf.jasperreports.engine.export.JRPdfExporter.exportPage(JRPdfExporter.java:1063) at net.sf.jasperreports.engine.export.JRPdfExporter.exportReportToStream(JRPdfExporter.java:927) at net.sf.jasperreports.engine.export.JRPdfExporter.exportReport(JRPdfExporter.java:547)[/code]Points from my investigation: - XLS export works just fine - When I remove all the grouping + sum variables, PDF works fine and all 3900 pages are printed - When I increase JVM memory, the report is generated but pdf is still corrupted and only first page works without lags I have found few similar issues on the internet, but not the solution. Anyone can help me please? Kind regards, Jan might be related to this topic: https://community.jaspersoft.com/questions/1155731/export-report-pdf-format https://community.jaspersoft.com/questions/525206/exportreporttopdffile-hangs-outofmemoryerror https://community.jaspersoft.com/questions/1163006/could-not-load-following-font