public ArrayList<String> getCourseStudents(String course) throws ClassNotFoundException{
        String student = null;
        Class.forName("org.sqlite.JDBC");
        String sql = null;
        Connection connection = null;
        Statement statement = null;
        ResultSet rs = null;
        ArrayList<String> retrieveStudent = new ArrayList<String>();

        try {
            // create a database connection
            connection = DriverManager.getConnection("jdbc:sqlite:sample.db");
            statement = connection.createStatement();
            statement.setQueryTimeout(30); // set timeout to 30 sec.

       rs = statement.executeQuery("SELECT DISTINCT student FROM endgrade WHERE course = '"+ course +"'");

       while(rs.next()){
       student = rs.getString("student");

       retrieveStudent.add(student);

       }

        }
        catch (SQLException e) {
            // if the error message is "out of memory",
            // it probably means no database file is found
            System.err.println(e.getMessage());

        } finally {
            try {
                if (connection != null)
                    connection.close();
            } catch (SQLException e) {
                // connection close failed.
                System.err.println(e);
            }
            }

        return retrieveStudent;
    }