我的java bean设计得对吗？

简单例子，与问题无关的都已省略:

/**部门表：department **/
create table Department(
DepNo char(9), /**主键，部门代号**/
DepUpperNo char(9) /**上级部门代号，无上级部门时为空**/
);

/* entry bean */
class Department{
private String depno;
Department depupper; //若无上级部门，为空
//....
//setters and getters
}

/* bean to operate the database */
class DepartmentMap{
public DepartmentMap(){}
public Department load(String DepNo){
//...Connect the database and construct the string sql
ResultSet rs=db.executeQuery(sql);
Department dep，depupper;
dep.setDepNo(rs.getString("DepNo"));
if (rs.getString("DepUpper")!=null){
DeparmtentMap dm;
depupper=dm.load(rs.getDate("DepUpper"));
}
else depupper=null;
dep.setDepDepUpper(depupper);
return dep;
}
//other functions...
}
调用load函数时，会递归执行下去，把所有的上级部门都实例化了，好象没有这个必要，很耗时啊。我这样设计对不对呢？不对，又该怎么改？
顺便问一句，DepartmentMap是不是设计成abstract class好一点？