java - JInternalFrame does not show up -

from mainframe create internal frame , add desktop pane, internal frame won't show up. tried figure out 3 hours , kinda need it. before implemented observer pattern worked fine. thought got , changed stuff , double checked crucial code. no solution far. realized how crappy english sometimes. sorry that!

the 2 code blocks shortened. sorry still pretty long. not sure made mistake. if need more code or else, tell me. thank in advance.

this code of main frame:

public class langtonsameise extends jframe implements actionlistener { private jdesktoppane desk; private jpanel panelbuttons; jmenubar jmb; jmenu file,modus; jmenuitem load,save, exit, msetzen,mmalen,mlaufen; jslider slider; static int xint, yint,xframe=450,yframe=450; static boolean bsetzen = false, bmalen = false, running = false;   random randomgenerator = new random();  jlabel xlabel, ylabel, speed, statustext,status; jbutton start, stop, addant; jtextfield xfield, yfield;  public langtonsameise() {     // desktop     desk = new jdesktoppane();     getcontentpane().add(desk, borderlayout.center); /*       4 lines work fine. internal frame gets displayed.     jinternalframe j = new jinternalframe();     desk.add(j);     j.setsize(new dimension(300,300));     j.setvisible(true);     */       speed = new jlabel("geschwindigkeit");      xlabel = new jlabel("x:");     ylabel = new jlabel("y:");     xlabel.sethorizontalalignment(jlabel.right);     ylabel.sethorizontalalignment(jlabel.right);     xlabel.setopaque(true);     ylabel.setopaque(true);     xfield = new jtextfield();     yfield = new jtextfield();      xfield.setdocument(new integerdocument(2));     yfield.setdocument(new integerdocument(2));      start = new jbutton("fenster erstellen");     stop = new jbutton("stopp");      start.setmargin(new insets(0, 0, 0, 0));     stop.setmargin(new insets(0, 0, 0, 0));     // buttons     panelbuttons = new jpanel();     panelbuttons.setlayout(new gridlayout());             panelbuttons.add(start);     panelbuttons.add(xlabel);     panelbuttons.add(xfield);     panelbuttons.add(ylabel);     panelbuttons.add(yfield);     panelbuttons.add(speed);     panelbuttons.add(slider);     panelbuttons.add(new panel());     panelbuttons.add(stop);      start.addactionlistener(this);     stop.addactionlistener(this);     add(panelbuttons, borderlayout.north);      statustext = new jlabel("aktueller modus:");     status = new jlabel("stopp");     // jmenubar     jmb = new jmenubar();     setjmenubar(jmb);     file = new jmenu("datei");     modus = new jmenu("modus");     mlaufen = new jmenuitem("laufen");     mmalen = new jmenuitem("malen");     msetzen = new jmenuitem("setzen");     load = new jmenuitem("simulation laden");     save = new jmenuitem("simulation speichern");      msetzen.addactionlistener(this);     mmalen.addactionlistener(this);     mlaufen.addactionlistener(this);     exit = new jmenuitem("exit");      file.add(save);     file.add(load);     file.addseparator();     file.add(exit);      save.addactionlistener(this);     load.addactionlistener(this);      modus.add(mlaufen);     modus.add(msetzen);     modus.add(mmalen);      jmb.add(file);     jmb.add(modus);     (int = 0; < 20; i++) {         jmb.add(new jlabel("    "));                 }      jmb.add(statustext);     jmb.add(status);     setsize(new dimension(1000, 900));      dimension dim = toolkit.getdefaulttoolkit().getscreensize();     this.setlocation(dim.width / 2 - this.getsize().width / 2, dim.height             / 2 - this.getsize().height / 2);     xfield.settext("5");     yfield.settext("5");     setvisible(true); }  public void actionperformed(actionevent e) {     if (e.getactioncommand().equals("fenster erstellen")) {          if (xfield.gettext().equals("") || yfield.gettext().equals("")) {             new popupwindow(                     "sie müssen eine zahl zwischen 2 und 99 angeben!!");         } else {             xint = integer.parseint(xfield.gettext());             yint = integer.parseint(yfield.gettext());             state s = new state();             kindfenster k = new kindfenster(s, xint, yint);             s.addobserver(k);             addchild(k, this.getsize().width, this.getsize().height);         }      }      if (e.getactioncommand().equals("stopp")) {         running=!running;         status.settext("stopp");     } }  public void addchild(jinternalframe kind, int xpixel, int ypixel) {     // kind.setsize(370, 370);     kind.setlocation(randomgenerator.nextint(xpixel - kind.getsize().height),             randomgenerator.nextint(ypixel - kind.getsize().height - 100));     kind.setdefaultcloseoperation(jinternalframe.dispose_on_close);     desk.add(kind);      kind.setvisible(true);     kind.repaint();     kind.validate(); }  public static void main(string[] args) {     langtonsameise hauptfenster = new langtonsameise();  }  } 

and internal frame:

    public class kindfenster extends jinternalframe implements actionlistener,     serializable,observer  { /**  *   */ private static final long serialversionuid = 8939449766068226519l; static int nr = 0; static int x,y,xscale,yscale,xframe,yframe; static int sleeptime; state s; arraylist<jbutton> jbarray = new arraylist<>(); arraylist<imageicon> ameisen = new arraylist<imageicon>(); public static arraylist<ameisethread> threadlist = new arraylist<>();  color altefarbe, neuefarbe; jbutton save, addant; jpanel panelbuttonskind; jslider sliderkind; public jpanel panelspielfeld;  static setzenactionlistener sal = new setzenactionlistener(); static mousemotionactionlistener mmal = new mousemotionactionlistener();  public kindfenster(state s,int x, int y) {     super("kind " + (++nr), true, true, true, true);     setlayout(new borderlayout());     this.s=s;      setsize(new dimension(xframe, yframe));      panelspielfeld = new jpanel();     panelspielfeld.setlayout(new gridlayout(y, x));      panelbuttonskind = new jpanel();     panelbuttonskind.setlayout(new gridlayout(1, 3));      save = new jbutton("simulation speichern");     addant = new jbutton("ameise hinzufügen");     save.setmargin(new insets(0, 0, 0, 0));     addant.setmargin(new insets(0, 0, 0, 0));      addant.addactionlistener(this);     save.addactionlistener(this);      sliderkind = new jslider(jslider.horizontal, 1, 10, 5);     sliderkind.setsnaptoticks(true);     sliderkind.setpaintticks(true);     sliderkind.setpainttrack(true);     sliderkind.setmajortickspacing(1);     sliderkind.setpaintlabels(true);      sliderkind.addchangelistener(new changelistener() {         @override         public void statechanged(changeevent e) {             if (threadlist.size() >= 0) {                 (ameisethread t : threadlist) {                     jslider source = (jslider) e.getsource();                     if (!source.getvalueisadjusting()) {                         int speed = source.getvalue();                         sleeptime = 1000 / speed;                     }                 }             }         }     });      panelbuttonskind.add(save);     panelbuttonskind.add(sliderkind);     panelbuttonskind.add(addant);     add(panelbuttonskind, borderlayout.north);     add(panelspielfeld, borderlayout.center);     this.addcomponentlistener(new mycomponentadapter());      setvisible(true);     repaint();     validate(); }    public void actionperformed(actionevent e) {      if (e.getactioncommand().equals("ameise hinzufügen")) {         threadlist.add(new ameisethread(this));         threadlist.get(threadlist.size() - 1).start();     }     if (e.getactioncommand().equals("simulation speichern")) {          outputstream fos = null;         try {             fos = new fileoutputstream("test");             objectoutputstream o = new objectoutputstream(fos);             o.writeobject(this  );         } catch (ioexception e1) {             system.err.println(e1);         } {             try {                 fos.close();             } catch (exception e1) {                 e1.printstacktrace();             }         }     } } 

i think because didn't set size jinternalframe. in code comment:

//kind.setsize(370, 370); 

when remove "//" works me.