// report gets one record, in letterFields
InputStream designFile = this.getClass().getResourceAsStream("myreport.rptdesign");
IReportRunnable design = engine.openReportDesign(designFile);
IRunAndRenderTask task = engine.createRunAndRenderTask(design);
RenderOption options = new RenderOption();
options.setOutputFormat("pdf");			
CircularByteBufferEx cbb = new CircularByteBufferEx(CircularByteBuffer.INFINITE_SIZE);
options.setOutputStream(cbb.getOutputStream());
task.setRenderOption(options);
// pull together data to pass to engine task
LetterBodyData lbd = new LetterBodyData();
lbd.load(letterFields);
Map<String, Object> parameters = new HashMap<String, Object>();
parameters.put("LetterBody", lbd);
task.setParameterValues(parameters);
// generate the output
task.run();
task.close();
cbb.getOutputStream().close();
// save the document
FileOutputStream fos = new FileOutputStream("c:\temp\myreport.pdf");
fos.write(cbb.getBuffer(), 0, cbb.getSize());
fos.close();