class Person...
private String lastName;
private String firstName;
private int numberOfDependents;


class AbstractMapper...
protected Map loadedMap = new HashMap();
abstract protected String findStatement();
protected DomainObject abstractFind(Long id) {
    DomainObject result = (DomainObject) loadedMap.get(id);
    if (result != null) return result;
    PreparedStatement findStatement = null;
    try {
        findStatement = DB.prepare(findStatement());
        findStatement.setLong(1, id.longValue());
        ResultSet rs = findStatement.executeQuery();
        rs.next();
        result = load(rs);
        return result;
    } catch (SQLException e) {
        throw new ApplicationException(e);
    } finally {
        DB.cleanUp(findStatement);
    }
}


class PersonMapper...
protected String findStatement() {
    return "SELECT " + COLUMNS +
        " FROM people" +
        " WHERE id = ?";
}
public static final String COLUMNS = " id, lastname, firstname, number_of_dependents ";
public Person find(Long id) {
    return (Person) abstractFind(id);
}
public Person find(long id) {
    return find(new Long(id));
}