КОД

 public class AccountDataServlet extends HttpServlet {

    private AccountService accountService;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        System.out.println("my servlet init() call");
        accountService = new AccountService();
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        HttpSession http = req.getSession(true);
        http.setMaxInactiveInterval(60);
        StringBuilder sb = new StringBuilder();
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter pw = resp.getWriter();
        sb.append("<html><body>");
        sb.append("<h1>Serlvet</h1>").append("<br>");
        sb.append("<h1>Before database reading....</h1>");
        try {
            for (String s : accountService.getAccountsShortInfo()) {
                sb.append(s);
            }
        } catch (DAOException e) {
            throw new IOException();
        } finally {
            sb.append("<h1>After database reading...</h1>");
            sb.append("</body><html>");
            resp.setStatus(HttpServletResponse.SC_OK);
            pw.append(sb.toString());
            pw.close();
        }
    }

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public class AccountService {

    private final AccountDAO accountDAO;

	public List<String> getAccountsShortInfo() throws DAOException {
        List<String> shortInfo = new ArrayList<>();
        for (Account a : accountDAO.getAll().values()) {
            String accountInfo = a.getName() + " " + a.getMiddleName() + " " + a.getEmail() + " " + a.getHomeAddress();
            shortInfo.add(accountInfo);
        }
        System.out.println(shortInfo.toString());
        return shortInfo;
    }
}

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public class AccountDAO extends DAO {

	public Map<Long, Account> getAll() throws DAOException {
        return super.getAll("SELECT * FROM account");
    }

	protected Account buildFromResult(ResultSet resultSet) throws SQLException {
        Account account;
        account = new Account(
                resultSet.getLong("account_id"),
                resultSet.getString("name"),
                resultSet.getString("middle_name"),
                resultSet.getString("last_name"),
                resultSet.getString("sex"),
                resultSet.getDate("birth_date").toLocalDate(),
                resultSet.getString("home_address"),
                resultSet.getString("work_address"),
                resultSet.getString("email"),
                resultSet.getString("skype"),
                resultSet.getString("additional_info")
        );
        return account;
    }

}

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abstract class DAO {

	public <E extends DataSet> Map<Long, E> getAll(String query) throws DAOException {
        Connection connection = manager.get();
        Map<Long, E> map = new HashMap<>();
        try (ResultSet resultSet = connection.createStatement().executeQuery(query)) {
            while (resultSet.next()) {
                E e = buildFromResult(resultSet);
                map.put(e.getId(), e);
            }
        } catch (SQLException e) {
            throw new DAOException(e);
        } finally {
            manager.closePool();
        }
        return map;
    }
}

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public class DAOException extends Exception {

    public DAOException(String text) {
        super(text);
    }

    public DAOException(Throwable cause) {
        super(cause);
    }

}