Problem while encoding JPEG image from JFrame paintComponent in a servlet

Question

Hello!
I m developing webapplication in which I made one servlet that calls JFrame developed by me, and then encoding into JPEG image to send response on client browser. I m working on NetBeans 5.5 and the same code runs well. But my hosting server is Linux and I m getting the following error:
java.awt.HeadlessException:
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
     java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:159)
     java.awt.Window.<init>(Window.java:406)
     java.awt.Frame.<init>(Frame.java:402)
     java.awt.Frame.<init>(Frame.java:367)
     javax.swing.JFrame.<init>(JFrame.java:163)
     pinkConfigBeans.pinkInfo.pinkModel.pinkChartsLib.PinkChartFrame.<init>(PinkChartFrame.java:36)
     pinkConfigBeans.pinkController.showLastDayRevenueChart.processRequest(showLastDayRevenueChart.java:77)
     pinkConfigBeans.pinkController.showLastDayRevenueChart.doGet(showLastDayRevenueChart.java:107)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.25 logs.
I m building the application in NetBeans and when runs then it runs well, even while browsing from LAN. But when I place the web folder creted under buil directory of NetBeans in the Tomcat on Linux, then it gives above error.
Under given is the servlet code raising exception
response.setContentType("image/jpeg"); // Assign correct content-type
ServletOutputStream out = response.getOutputStream();
/* TODO GUI output on JFrame */
PinkChartFrame pinkChartFrame;
pinkChartFrame = new PinkChartFrame(ssnGUIAttrInfo.getXjFrame(), ssnGUIAttrInfo.getYjFrame(), headingText, xCordText, yCordText, totalRevenueDataList);
pinkChartFrame.setTitle("[::]AMS MIS[::] Monthly Revenue Chart");
pinkChartFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//pinkChartFrame.setVisible(true);
//pinkChartFrame.plotDataGUI();
int width = 760;
int height = 460;
try {
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
pinkChartFrame.pinkChartJPanel.paintComponent(g2);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
} catch (ImageFormatException ex) {
ex.printStackTrace();
response.sendRedirect("index.jsp");
} catch (IOException ex) {
ex.printStackTrace();
response.sendRedirect("index.jsp");
out.flush();
Do resolve anybody!
Edited by: pinkVag on Oct 15, 2007 10:19 PM

Answer 1

>
I m developing webapplication in which I made one servlet that calls JFrame developed by me, and then encoding into JPEG image to send response on client browser. I m working on NetBeans 5.5 and the same code runs well. But my hosting server is Linux and I m getting the following error:
java.awt.HeadlessException: >That makes sense. It is saying that you cannot open a JFrame in an environment (the server) that does not support GUIs!
To make this so it will work on the server, it will need to be recoded so that it uses the command line only - no GUI.
What is it exactly that PinkChartFrame is generated an image of? What does it do? (OK probably 'generate a chart') But what APIs does it use (JFreeChart or such)?