[Java/SWING] Probleme de Thread

    private native void natStep(int numbSteps) ; 

	stepThread NST = new stepThread() ;
	for (i=0;i<NUMBER_OF_STEPS;i++)
	{
		refreshControl() ;
		NST.start() ;
		try{
		NST.join(10) ;
		}
		catch (InterruptedException ie) {}
	}//End of for
    }

    class stepThread extends Thread
    {
    	stepThread(){}
	public void run()
	{
		natStep(1) ;
	}
    }

AWT-EventQueue-0" java.lang.IllegalThreadStateException

class refresh extends Thread
{
    private int nbTour;
    refresh( int nbTour ){
        this.nbTour = nbTour;
   }
   public void run()
  {
      for(int i=0;i<nbTour;i++) {
        refreshControl() ;
        try {
             sleep(100);
       }
        catch( Exception e ){ ; }
      }
   }
}
                       
class natStep extends Thread
{
    private int nbTour;
    natStep( int nbTour ){
        this.nbTour = nbTour;
   }
   public void run()
  {
      for(int i=0;i<nbTour;i++) {
        natStep(1) ;
        try {
             sleep(100);
       }
        catch( Exception e ){ ; }
      }
   }
}

Et pour ton principal :
 netStep n = new netStep(NUMBER_OF_STEPS);
 refresh r = nes refresh(NUMBER_OF_STEPS);
 n.start();
 r.start();
 n.join();
 r.join();