package exercise3Lib_8140058;

import java.sql.*;
import java.io.*;

public class UserDAO_EX3_8140058 {

    private String errorMessages = "";

    private PreparedStatement stmt = null;

    private ResultSet rs = null;

    private Connection con = null;

    private final String userQuery = "select username from user_8xxxxxx where username =? and password=?";

    private String usern, passw, email;

    public User authenticateUser(String username, String password) throws Exception {

        DB_EX3_8140058 dataB = new DB_EX3_8140058();

        dataB.open();
        con = dataB.getConnection();

        try {

            stmt = con.prepareStatement(userQuery);
            // replacing the first ? with username and the second ? with
            // password
            stmt.setString(1, username);
            stmt.setString(2, password);
            // execute query
            rs = stmt.executeQuery();

            int counter = 0;

            while (rs.next())
                counter++;

            if (counter == 1) {
                User userVal = new User(rs.getString("username"),rs.getString("password"),rs.getString("email"));
                stmt.close();
                rs.close();
                con.close();
                dataB.close();
                return userVal;
            } else {
                stmt.close();
                rs.close();
                con.close();
                dataB.close();
                throw new Exception("Wrong username or password");
            }
        } catch (SQLException ex)  {
            ex.printStackTrace();
        }
    }
}


Compile Error:
C:\Users\JIM\Desktop\exercise3Lib_8140058\UserDAO_EX3_8140058.java:59: error: missing return statement
    }
    ^
1 error

Tool completed with exit code 1