code: public void addAttr(String attr, Object val) throws NamingException {
  //  System.out.println("addAttr " + attr);
  
      Attribute a = findAttr(attr);
  
      if (a == null) {
        setAttr(attr, val);
      } else {
        a.add(val);
      }
    }
docs: Add the attribute value to the table. If an attribute already exists
  add it to the end of its values.
  
  @param   attr   String attribute name
  @param   val    Object value
  @throws NamingException