Ругается - java.lang.NullPointerException

    teacherColumnID.setCellValueFactory(new PropertyValueFactory<TeacherTableData,String>("teacherTableDataID"));
        teacherColumnName.setCellValueFactory(new PropertyValueFactory<TeacherTableData,String>("teacherTableDataName"));
        teacherColumnGPA.setCellValueFactory(new PropertyValueFactory<TeacherTableData,String>("teacherTableDataGPA"));
        teacherColumnPhone.setCellValueFactory(new PropertyValueFactory<TeacherTableData,String>("teacherTableDataPhone"));
        teacherEmail.setCellValueFactory(new PropertyValueFactory<TeacherTableData,String>("teacherTableDataEmail"));
 
        String teacherSecs[]=null,teacherSec=null;
 
        try {
            connection = database.getConnection();
            statement = connection.createStatement();
            resultSet = statement.executeQuery("SELECT * FROM teacher WHERE dbTeacherEmail = '"+email+"';");
            while (resultSet.next()){
                teacherSec=resultSet.getString("dbTeacherCourse");
            }
            if (teacherSec.contains(",")){
                teacherSecs = teacherSec.split(",",0);
            }
            else if (!teacherSec.isEmpty()){
                teacherSecs[0] = teacherSec; //ругается тут ошибка сверху 
            }
            else {
                System.out.println("There is no teacher sec");
            }
 
            ObservableList<String> sec = FXCollections.observableArrayList(teacherSecs);
            teacherTableSecChoose.setItems(sec);
            connection.close();
            statement.close();
            resultSet.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        teacherTableSecChoose.getSelectionModel().select(teacherSecs[0]);
        setCourseID(teacherSecs[0]);
 
        teacherTableView.setItems(getDataFromTeacherTableDataAndAddToObservableList(teacherSecs[0]));
 
 
    }