java - Internal widows don't show up in desktop pane -

after little research on internet, created desktop pane , want put internal frames. use factory pattern create multiple internal frames (windows)

i have abstract class

import javax.swing.*; public abstract class internalwindowtemplate extends jinternalframe{ jinternalframe internalwindow;  public final void createinternalwindow(string title, int width, int height, int xoffset, int yoffset, boolean isresizable, boolean isclosable, boolean ismaximizable, boolean isiconifiable){     internalwindow = new jinternalframe(title, isresizable, isclosable, ismaximizable, isiconifiable);      setinternalwindowsize(width, height);     setinternalwindowlocation(xoffset, yoffset);     internalwindow.setvisible(true);     internalwindow.setdefaultcloseoperation(jinternalframe.exit_on_close);      try {         internalwindow.setselected(true);      }       catch (java.beans.propertyvetoexception exception) {          exception.getmessage();      }      catch(exception exception){          exception.getmessage();      } }  public void setinternalwindowlocation(int xoffset, int yoffset){     setlocation(xoffset*getinternalwindowcounter(), yoffset*getinternalwindowcounter()); }  public void setinternalwindowsize(int width, int height){     setsize(width,height); } } 

and create commandwindow:

import internalframe.*; import javax.swing.*;  public class commandwindow extends internalwindowtemplate {    public commandwindow(){     createinternalwindow("command window", 60, 40, 30, 30, false, true, false, false);    } } 

finally, create view gui

import java.awt.*; import javax.swing.*;  public class desktopview extends jframe{ private jdesktoppane desktop; internalwindowtemplate commandwindow;  public desktopview(){     //make big window indented 50 pixels each edge of screen.     int inset = 50;     dimension screensize = toolkit.getdefaulttoolkit().getscreensize();     setbounds(inset, inset, screensize.width  - inset*2, screensize.height - inset*2);      //set gui.     desktop = new jdesktoppane();     commandwindow = new commandwindow();     desktop.add(commandwindow);     setcontentpane(desktop); } } 

when try run in main

public class desktopapp { public static void main(string[] agrs){     desktopview desktopview = new desktopview();     desktopview.setvisible(true);     desktopview.setdefaultcloseoperation(desktopview.exit_on_close); } } 

i "big" window, not internals. doing wrong? there don't see? suggestions appreciated. thank in advance