TreeSet tStp = new TreeSet();
        try {
            ...
            if (rs.next()){
                SalesType st = new SalesType();
                while(rs.next()){
                  st.StpID = rs.getInt( 1 );
                  st.StpName = rs.getString( 2 );
                  tStp.add(st);
                }
            }
        }

 public   class  SalesType {
...
     static  StpComparator stpComparator =  new   StpComparator();    
     
     public   static  Comparator getStpComparator() {
         return  stpComparator;
    }    
    
      static   class  StpComparator  implements  Comparator {
           public   int  compare(Object o1, Object o2) {
                 return  ((SalesType)o1).StpID - ((SalesType)o2).StpID;
          }
     }     
...
}

     public  TreeSet getStp(){
        SalesType st =  new  SalesType();
        TreeSet tStp =  new  TreeSet(st.getStpComparator());
        
         try  {
            ...
             if  (rs.next()){
                 while (rs.next()){
                  st.StpID = rs.getInt( 1 );
                  st.StpName = rs.getString( 2 );
                  tStp.add(st);
                }
            }
        }
   }

               TreeSet tStp = dbm.getStp();
               Iterator e = tStp.iterator();
                while  (e.hasNext()){
                      SalesType eStp = (SalesType)e.next();
                       if  (user.Stp == eStp.getStpID()){
                      ...
                      }
               }