java - Swing Graphics object not drawing over image in JLabel -

i creating java program receives , plots gps coordinates on tcp socket connection on 2d image of map. constructor creates jframe , graphical components , starts off swingworker thread handle getting coordinates socket , drawing oval represent fix on map.

i able receive data on connection program not reliably draw points on image.

any suggestions , thank you!

import java.awt.color; import java.awt.graphics; import java.awt.image; import java.io.file; import java.util.list;  import javax.imageio.imageio; import javax.swing.imageicon; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.swingworker;  import connectivity.telitsocketserver; import calculations.plottingmath; import objects.elephantfix;  @suppresswarnings("serial") public class gui  {     protected jframe mainwindow;      protected jpanel maparea = new jpanel();      private receivefix rfix;      public gui()     {         // todo auto-generated constructor stub          mainwindow =  new jframe();          // load map image         image map = null;         try         {             file mapimage = new file("map_images/awe_plot.jpg");             map = imageio.read(mapimage);          } catch (exception e)         {             system.out.println(e.tostring());         }            jlabel label = new jlabel(new imageicon(map));         maparea.add(label);           // map image dimensions          mainwindow.getcontentpane().add(maparea, "center");          mainwindow.setsize(471, 670);         mainwindow.setdefaultcloseoperation(jframe.exit_on_close);         mainwindow.settitle("eleplotter");         mainwindow.setvisible(true);          rfix = new receivefix();         rfix.execute();  }  public static void main(string args[]) {        new gui();   }  private class receivefix extends swingworker<void, elephantfix> {      @override     protected void doinbackground()     {         // start server         string fix = "";          telitsocketserver currentconnection = new telitsocketserver();         try         {             // wait client connect             currentconnection.intializeconnection();              while (true)             {                 // parse , convert received gps fix arc radians                   fix = currentconnection.readline();                  string[] split = fix.split(" ");                   double latwholedegrees = double.parsedouble(split[0]                         .substring(0, 3));                 double longwholedegrees = double.parsedouble(split[1]                         .substring(0, 3));                  double latminutes = double.parsedouble(split[0]                         .substring(3)) * .166667;                 double longminutes = double.parsedouble(split[1]                         .substring(3)) * .166667;                   double lat = latwholedegrees - latminutes / 10;                 double lon = longwholedegrees + longminutes / 10;                  publish(new elephantfix(lat, lon));             }          } catch (exception e)         {              e.printstacktrace();         }          // return null if somehow unable publish node data         return null;      }       @override     protected void process(list<elephantfix> fixes)     {         int x, y;         // published node         elephantfix afix = fixes.get(fixes.size() - 1);            // translate lat/long map x/y pixel         x = plottingmath.getcurrentpixelx(afix.getlatitude(),                 afix.getlongitude());         y = plottingmath.getcurrentpixely(afix.getlatitude(),                 afix.getlongitude());           // plot on image         graphics g = maparea.getgraphics();          g.setcolor(color.red);          g.filloval(x, y, 15, 15);          // maparea.validate();         //         // maparea.repaint();         //         // gui.this.repaint();      } }  } 

you should not drawing graphics object obtained calling getgraphics() on component. doing give graphics object doesn't persist , image doesn't persist. instead either draw on bufferedimage graphics object , display in gui, or iterate through data collection in jpanel's paintcomponent method , draw data obtained.