Here is a Java sample code showing how to export images of pages in a PDF document (in jpg, png or tiff format) using jPDFViewer. jPDFViewer is a Java Swing component that can display PDF documents and also allows to get page images from a PDF document as BufferedImage objects which can then be saved to image files using ImageIO.

// create the PDF Viewer Bean
PDFViewerBean viewerBean = new PDFViewerBean();
// load a PDF document into the bean
// get the Document object
IPDFDocument document = viewerBean.getDocument();       
// loop through all the pages in the PDF document
for(int count = 0; count < document.getPageCount(); count++)
 // get the current page
 IPDFPage page = document.getIPage(count);
 // get width and height
 int width = (int) page.getDisplayWidth();
 int height = (int) page.getDisplayHeight();
 // get the image from the current page as a BUfferedImage object
 BufferedImage pageImage = page.getImage(width, height, false );
 // save the image to a file (here in jpeg format)
 File outputfile = new File("C:\\test\\image_" + (count+1) + ".jpg");
 ImageIO.write(pageImage, "jpg", outputfile);