java - trying to make object of class and then to display.setCurrent(Class) but not working -

i trying make new object startgame , show in gamemidlet class, whenever click on ok button display content of startgame, screen doesn't show anything, instead showing same gamemidlet menu. please me find bug is. thank in advance.

public class gamemidlet extends midlet implements commandlistener, itemcommandlistener  {  gamecanvas gamecanvasnew; display display;  startgame startgame;  command restartcommand; vector mgamecanvaslist; gamecanvas gamecanvassecond;  private form formmenu;  private command exitcommand; private command okcommand; private command exitcommandgame;  private stringitem menuitem; private stringitem sinewgameitem; private stringitem siresume; private stringitem siexit;  public void startapp() {      formmenu = new form("start menu", new item[] {getnewgameitem(), getresumeitem(), getexititem()});     display  = display.getdisplay(this);       display.setcurrent(formmenu);   }  public void pauseapp() { }  public void destroyapp(boolean unconditional) { }  public void commandaction(command c, displayable d) {       }   public stringitem getnewgameitem(){      if(sinewgameitem == null){         sinewgameitem = new stringitem("new game","", item.button);         sinewgameitem.addcommand(getokcommand());         sinewgameitem.setitemcommandlistener(this);     }      return sinewgameitem;  }  public stringitem getresumeitem(){      if(siresume == null){         siresume = new stringitem("resume", "", item.button);         siresume.addcommand(getokcommand());         siresume.setitemcommandlistener(this);     }      return siresume; }  public stringitem getexititem(){      if(siexit == null){         siexit = new stringitem("exit","",item.button);         siexit.addcommand(getexitcommand());         siexit.setitemcommandlistener(this);     }      return siexit; }  public command getokcommand(){      if(okcommand == null){          okcommand = new command("ok", command.ok, 0);     }      return okcommand;  }  public command getexitcommand(){      if(exitcommand == null){         exitcommand = new command("exit", command.exit, 0);     }     return exitcommand; }  public void commandaction(command c, item item) {      if(item == siexit){         if(c == exitcommand){             destroyapp(true);             notifydestroyed();         }     }      else if(item == sinewgameitem){             if(c == okcommand){                  // having problem @ here......                 startgame = new startgame();                  display.setcurrent(startgame);                 startgame.startgamenew();              }         }       } } 

startgame.java

public class startgame extends canvas implements commandlistener {  gamecanvas game; display display; command exitcommand; command restartcommand; vector mgamecanvaslist; gamecanvas fistlist;   public void startgamenew() {       game = new gamecanvas();       exitcommand     = new command("exit", command.exit, 0);     restartcommand  = new command("restart", command.ok, 0);      game.addcommand(exitcommand);     game.addcommand(restartcommand);      game.setcommandlistener(this);     game.setcommandlistener(this);     game.startthread();  }   protected void paint(graphics g) {  } }