sqlClassLoader cl =  new  sqlClassLoader(ClassLoader.getSystemClassLoader());
cl.reInit();
Object dd = cl.loadClass("StartWindow").newInstance();
JInternalFrame a = (JInternalFrame)dd;
getContentPane().removeAll();
getContentPane().repaint();
getContentPane().add(a);

 Class  cc = cl.loadClass("StartWindow");
Object dd = cc.newInstance();
JInternalFrame a = (JInternalFrame)dd; 
getContentPane().add(a);       
a.setVisible(true);

 Class  cc = cl.loadClass("StartWindow");
Object dd = cc.newInstance();
ConnectedInternalFrame a = (ConnectedInternalFrame)dd; 
a.SetConn(conn);
getContentPane().add(a);       
a.setVisible(true);

 public   class  ConnectedInternalFrame  extends  JInternalFrame  implements  SetConnection {
    
    /** Creates a new instance of ConnectedInternalFrame */
     public  ConnectedInternalFrame() {
    }
    
     public   void  SetConn(Connection c){
        conn = c;
    }
     protected  Connection conn;
}