Ошибка при запуске приложения Javafx

Question

Здравствуйте, я новичок в Java и получаю сообщение об ошибке при запуске приложения. Приложение запускается, но когда вызывается событие нажатия кнопки createStudent(ActionEvent event), отображаются ошибки. Я вставляю полную трассировку стека ошибок.

javafx.fxml.LoadException: 
/home/user/IdeaProjects/JavaFxDemo/out/production/JavaFxDemo/resources/fxml/newStudent.fxml 

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601) 
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2571) 
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441) 
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409) 
    at dashboard.Controller.createStudent(Controller.java:145) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769) 
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Node.fireEvent(Node.java:8411) 
    at javafx.scene.control.Button.fire(Button.java:185) 
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89) 
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3757) 
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485) 
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762) 
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:352) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:388) 
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:387) 
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555) 
    at com.sun.glass.ui.View.notifyMouse(View.java:937) 
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method) 
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.reflect.InvocationTargetException 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2566) 
    ... 65 more 
Caused by: java.sql.SQLException: Operation not allowed after ResultSet closed 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910) 
    at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:666) 
    at com.mysql.jdbc.ResultSet.next(ResultSet.java:7274) 
    at dashboard.AdmissionController.initialize(AdmissionController.java:168) 
    ... 75 more 

Я проверил, есть ли какие-либо проблемы с файлом FXML в поле ниже места, но нет никакой проблемы.

javafx.fxml.LoadException: 
/home/user/IdeaProjects/JavaFxDemo/out/production/JavaFxDemo/resources/fxml/newStudent.fxml 

Пожалуйста, проверьте мои файлы контроллера

dashboard.Controller.java

package dashboard; 

import java.io.IOException; 
import java.net.URL; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.util.IdentityHashMap; 
import java.util.Observable; 
import java.util.ResourceBundle; 
import javafx.collections.FXCollections; 
import javafx.collections.ObservableList; 
import javafx.event.ActionEvent; 
import javafx.fxml.FXML; 
import javafx.fxml.FXMLLoader; 
import javafx.scene.Parent; 
import javafx.scene.Scene; 
import javafx.scene.control.Button; 
import javafx.scene.control.TextField; 
import javafx.scene.control.TableColumn; 
import javafx.scene.control.TableView; 
import dashboard.StudentMaster; 
import database.DatabaseAccess; 
import javafx.scene.control.cell.PropertyValueFactory; 
import javafx.stage.Modality; 
import javafx.stage.Stage; 
import javafx.stage.StageStyle; 

import java.sql.Connection; 

public class Controller { 


    private Connection connection; 

    @FXML 
    private ResourceBundle resources; 

    @FXML 
    private URL location; 

    @FXML 
    private TableView<StudentMaster> studentTable; 

    @FXML 
    private TableColumn<StudentMaster, Integer> studID; 

    @FXML 
    private TableColumn<StudentMaster, String> studReg; 

    @FXML 
    private TableColumn<StudentMaster, String> stdAdm; 

    @FXML 
    private TableColumn<StudentMaster, String> stdName; 

    @FXML 
    private TableColumn<StudentMaster, String> stdClass; 

    @FXML 
    private TableColumn<StudentMaster, String> stdDiv; 

    @FXML 
    private TextField regBox; 

    @FXML 
    private TextField admBox; 

    @FXML 
    private TextField nameBox; 

    @FXML 
    private TextField classBox; 

    @FXML 
    private TextField divBox; 

    @FXML 
    private Button searchBtn; 

    @FXML 
    private Button createStudentBtn; 

    private ObservableList<StudentMaster> data; 



    public void buildData(String SQL) 
    { 
     data = FXCollections.observableArrayList(); 
     try { 
      ResultSet rs = connection.createStatement().executeQuery(SQL); 
      while(rs.next()) 
      { 
       StudentMaster studentData = new StudentMaster(); 
       studentData.studentId.set(rs.getInt("student_id")); 
       studentData.stdClass.set(rs.getString("student_std")); 
       studentData.name.set(rs.getString("student_name")); 
       studentData.admNo.set(rs.getString("student_admn_no")); 
       studentData.regno.set(rs.getString("student_regno")); 
       studentData.stdDiv.set(rs.getString("student_div")); 
       data.add(studentData); 
       studentTable.setItems(data); 
      } 
     } catch (SQLException e) { 
      e.printStackTrace(); 
     } 
    } 

    @FXML 
    void initialize() { 
     assert studentTable != null : "fx:id=\"studentTable\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert studID != null : "fx:id=\"studID\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert studReg != null : "fx:id=\"studReg\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert stdAdm != null : "fx:id=\"stdAdm\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert stdName != null : "fx:id=\"stdName\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert stdClass != null : "fx:id=\"stdClass\" was not injected: check your FXML file 'dashboard.fxml'."; 
     assert stdDiv != null : "fx:id=\"stdDiv\" was not injected: check your FXML file 'dashboard.fxml'."; 

     DatabaseAccess newConnection = new DatabaseAccess(); 
     connection = newConnection.startConnection(); 
     String SQL = "Select * from student"; 
     buildData(SQL); 
     newConnection.shutdown(); 

     loadDataToTable(); 

    } 

    private void loadDataToTable() 
    { 
     studID.setCellValueFactory(new PropertyValueFactory<StudentMaster, Integer>("studentId")); 
     studReg.setCellValueFactory(new PropertyValueFactory<StudentMaster, String>("regno")); 
     stdName.setCellValueFactory(new PropertyValueFactory<StudentMaster, String>("name")); 
     stdAdm.setCellValueFactory(new PropertyValueFactory<StudentMaster, String>("admNo")); 
     stdClass.setCellValueFactory(new PropertyValueFactory<StudentMaster, String>("stdClass")); 
     stdDiv.setCellValueFactory(new PropertyValueFactory<StudentMaster, String>("stdDiv")); 
    } 

    @FXML 
    void createStudent(ActionEvent event) 
    { 
     FXMLLoader fxmlLoader; 
     fxmlLoader = new FXMLLoader(getClass().getResource("/resources/fxml/newStudent.fxml")); 
     try { 
      Parent root1 = (Parent)fxmlLoader.load(); 
      AdmissionController admissionController = fxmlLoader.getController(); 
      admissionController.setStudentData(studentTable.getItems()); 
      Stage stage = new Stage(); 
      stage.initModality(Modality.APPLICATION_MODAL); 
//   stage.initStyle(StageStyle.UNDECORATED); 
      stage.setTitle("New Admission"); 
      stage.setScene(new Scene(root1)); 
      stage.show(); 
     } catch (IOException e) 
     { 
      e.printStackTrace(); 
     } 
    } 

    @FXML 
    void searchBtnClicked(ActionEvent event) 
    { 
     String name = nameBox.getText(); 
     String regno = regBox.getText(); 
     String admno = admBox.getText(); 
     String stdClass = classBox.getText(); 

     String SQL = "Select * from student where student_name like '"+name+"%'"; 
     System.out.println(SQL); 
     DatabaseAccess newConnection = new DatabaseAccess(); 
     connection = newConnection.startConnection(); 
     buildData(SQL); 
     newConnection.shutdown(); 
     loadDataToTable(); 
    } 

    public void reloadStudentTable() 
    { 
     loadDataToTable(); 
    } 

} 

dashboard.AdmissionController.java

package dashboard; 

import javafx.beans.property.SimpleStringProperty; 
import javafx.collections.FXCollections; 
import javafx.collections.ObservableList; 
import javafx.event.ActionEvent; 
import javafx.fxml.FXML; 
import javafx.scene.Node; 
import javafx.scene.control.Button; 
import javafx.scene.control.ChoiceBox; 
import javafx.scene.control.DatePicker; 
import javafx.scene.control.TextArea; 
import javafx.scene.control.TextField; 
import javafx.scene.input.InputMethodEvent; 
import javafx.scene.input.MouseEvent; 
import javafx.stage.Stage; 
import customlib.ExecuteSQL; 
import dashboard.AvailableClasses; 

import java.sql.ResultSet; 
import java.sql.SQLException; 

public class AdmissionController { 


    @FXML 
    private TextField nameBox; 

    @FXML 
    private ChoiceBox<String> classBox; 

    @FXML 
    private ChoiceBox<String> divBox; 

    @FXML 
    private TextField admBox; 

    @FXML 
    private TextField religionBox; 

    @FXML 
    private TextField casteBox; 

    @FXML 
    private TextArea addressBox; 

    @FXML 
    private DatePicker dobBox; 

    @FXML 
    private ChoiceBox<?> sexBox; 

    @FXML 
    private Button resetBtn; 

    @FXML 
    private Button cancelBtn; 

    @FXML 
    private Button doneBtn; 

    @FXML 
    void cancelBtnClicked(ActionEvent event) 
    { 
//  GET the current node of the event 
     Node node = (Node)event.getSource(); 
     Stage stage = (Stage)node.getScene().getWindow(); 
     stage.close(); 
    } 

    @FXML 
    void classMouseClicked(MouseEvent event) throws SQLException { 
     System.out.println("clicked"); 
    } 

    private ObservableList<StudentMaster> data ; 
    private ObservableList<AvailableClasses>totalClasses; 

    public void setStudentData(ObservableList<StudentMaster> data) 
    { 
     this.data = data ; 
    } 

    @FXML 
    void doneBtnClicked(ActionEvent event) 
    { 
     String name = nameBox.getText(); 
     Integer ref = 1; 
     String standard = "1"; 
     String division = "A"; 
     String admissionNo = admBox.getText(); 
     String sex = "M"; 
     String religion = religionBox.getText(); 
     String caste = casteBox.getText(); 
     String address = addressBox.getText(); 
     String SQLquery = "INSERT INTO student (student_name," + 
       "fk_grp_ref,"+ 
       "student_std," + 
       "student_div," + 
       "student_admn_no," + 
       "student_sex," + 
       "student_religion," + 
       "student_caste," + 
       "student_address) " + 
       "VALUES ('"+name+"','"+ref+"', '"+standard+"'," + 
       " '"+division+"', '"+admissionNo+"', '"+sex+"', " + 
       "'"+religion+"', '"+caste+"', '"+address+"')"; 

     ExecuteSQL newQuery = new ExecuteSQL(); 
     Integer executeStatus = newQuery.ExecuteSQL(SQLquery); 
     if (executeStatus != 0) 
     { 
      System.out.println("Data Inserted"); 
     } 
     else 
     { 
      System.out.println("Error in execution"); 
     } 
     StudentMaster student = new StudentMaster(); 
     StudentMaster studentData = new StudentMaster(); 
     studentData.name.set(name); 
     studentData.admNo.set(admissionNo); 
     studentData.stdDiv.set(division); 
     studentData.stdClass.set(standard); 
     studentData.studentId.set(executeStatus); 
     data.add(studentData); 




//  Close the Window after successfully inserted 

     Node node = (Node)event.getSource(); 
     Stage stage = (Stage)node.getScene().getWindow(); 
     stage.close(); 

    } 

    @FXML 
    void resetBtnClicked(ActionEvent event) { 
     nameBox.setText(""); 
     addressBox.setText(""); 
     admBox.setText(""); 
     dobBox.getEditor().clear(); 
     religionBox.setText(""); 
     casteBox.setText(""); 
    } 

    @FXML 
    void initialize() throws SQLException { 
     assert nameBox != null : "fx:id=\"nameBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert classBox != null : "fx:id=\"classBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert divBox != null : "fx:id=\"divBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert admBox != null : "fx:id=\"admBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert religionBox != null : "fx:id=\"religionBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert casteBox != null : "fx:id=\"casteBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert addressBox != null : "fx:id=\"addressBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert dobBox != null : "fx:id=\"dobBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert sexBox != null : "fx:id=\"sexBox\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert resetBtn != null : "fx:id=\"resetBtn\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert cancelBtn != null : "fx:id=\"cancelBtn\" was not injected: check your FXML file 'newStudent.fxml'."; 
     assert doneBtn != null : "fx:id=\"doneBtn\" was not injected: check your FXML file 'newStudent.fxml'."; 

     String query = "select * from class"; 
     ExecuteSQL newSelectClassesQuery = new ExecuteSQL(); 
     ResultSet rs = newSelectClassesQuery.GetClassesList(query); 
     totalClasses = FXCollections.observableArrayList(); 
     while(rs.next()) 
     { 
//   AvailableClasses classesData = new AvailableClasses(); 
      classBox.getItems().add(rs.getString("class_name")); 
     } 
     rs.close(); 
    } 
} 

ExecuteSQL.java // Для того, чтобы выполнить мой SQL запросов

package customlib; 


import database.DatabaseAccess; 

import java.sql.*; 

public class ExecuteSQL { 
    private Connection connection; 

    public Integer ExecuteSQL(String query) 
    { 
     DatabaseAccess newConnection = new DatabaseAccess(); 
     connection = newConnection.startConnection(); 
     try 
     { 
      PreparedStatement preparedStatement = (PreparedStatement) connection.prepareStatement(query); 
      preparedStatement.executeUpdate(); 

      ResultSet rs = connection.createStatement().executeQuery("select last_insert_id() as last_id from student"); 
      int lastid = 0; 
      while(rs.next()) 
      { 
       lastid = rs.getInt("last_id"); 

      } 

      newConnection.shutdown(); 
      return lastid; 

     } 
     catch (SQLException e) 
     { 
      e.printStackTrace(); 
      newConnection.shutdown(); 
      return 0; 
     } 


    } 

    public ResultSet GetClassesList(String query) 
    { 
     DatabaseAccess newConnection = new DatabaseAccess(); 
     connection = newConnection.startConnection(); 
     ResultSet rs; 
     try 
     { 
      rs = connection.createStatement().executeQuery(query); 
      newConnection.shutdown(); 
      rs.close(); 
      return rs; 

     } 
     catch (SQLException e) 
     { 
      e.printStackTrace(); 
      newConnection.shutdown(); 
      rs = null; 
      return rs; 
     } 

    } 




} 

EDIT: Добавление newStudent.fxml файла

<?xml version="1.0" encoding="UTF-8"?> 

<?import javafx.scene.control.Button?> 
<?import javafx.scene.control.ChoiceBox?> 
<?import javafx.scene.control.DatePicker?> 
<?import javafx.scene.control.Label?> 
<?import javafx.scene.control.TextArea?> 
<?import javafx.scene.control.TextField?> 
<?import javafx.scene.layout.Pane?> 
<?import javafx.scene.text.Font?> 

<Pane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="500.0" prefWidth="700.0" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="dashboard.AdmissionController"> 
    <children> 
     <Pane layoutX="67.0" layoutY="92.0"> 
     <children> 
      <TextField fx:id="nameBox" layoutX="64.0" layoutY="1.0" /> 
      <ChoiceBox fx:id="classBox" layoutX="299.0" onMouseClicked="#classMouseClicked" prefHeight="26.0" prefWidth="61.0" /> 
      <ChoiceBox fx:id="divBox" layoutX="396.0" layoutY="1.0" prefHeight="26.0" prefWidth="61.0" /> 
      <Label layoutY="6.0" prefHeight="16.0" prefWidth="49.0" text="Name" /> 
      <Label layoutX="257.0" layoutY="6.0" prefHeight="16.0" prefWidth="38.0" text="Class" /> 
      <Label layoutX="368.0" layoutY="5.0" prefHeight="16.0" prefWidth="38.0" text="Div" /> 
      <TextField fx:id="admBox" layoutX="64.0" layoutY="52.0" /> 
      <Label layoutX="2.0" layoutY="57.0" prefHeight="16.0" prefWidth="61.0" text="Adm.No" /> 
      <TextField fx:id="religionBox" layoutX="64.0" layoutY="98.0" /> 
      <Label layoutX="2.0" layoutY="103.0" prefHeight="16.0" prefWidth="61.0" text="Religion" /> 
      <TextField fx:id="casteBox" layoutX="63.0" layoutY="145.0" /> 
      <Label layoutX="1.0" layoutY="150.0" prefHeight="16.0" prefWidth="61.0" text="Caste" /> 
      <Label layoutX="251.0" layoutY="58.0" prefHeight="16.0" prefWidth="61.0" text="Address" /> 
      <TextArea fx:id="addressBox" layoutX="306.0" layoutY="50.0" prefHeight="116.0" prefWidth="267.0" /> 
      <Label layoutX="1.0" layoutY="196.0" prefHeight="16.0" prefWidth="61.0" text="DOB" /> 
      <DatePicker fx:id="dobBox" layoutX="61.0" layoutY="192.0" prefHeight="26.0" prefWidth="170.0" /> 
      <ChoiceBox fx:id="sexBox" layoutX="500.0" layoutY="1.0" prefHeight="26.0" prefWidth="61.0" /> 
      <Label layoutX="472.0" layoutY="5.0" prefHeight="16.0" prefWidth="38.0" text="Sex" /> 
      <Button fx:id="resetBtn" layoutX="2.0" layoutY="272.0" mnemonicParsing="false" onAction="#resetBtnClicked" text="Reset" /> 
      <Button fx:id="cancelBtn" layoutX="425.0" layoutY="271.0" mnemonicParsing="false" onAction="#cancelBtnClicked" text="Cancel" /> 
      <Button fx:id="doneBtn" layoutX="512.0" layoutY="269.0" mnemonicParsing="false" onAction="#doneBtnClicked" prefHeight="26.0" prefWidth="62.0" text="Done" /> 
     </children> 
     </Pane> 
     <Label layoutX="261.0" layoutY="40.0" prefHeight="25.0" prefWidth="170.0" text="NEW ADMISSION"> 
     <font> 
      <Font size="20.0" /> 
     </font> 
     </Label> 
    </children> 
</Pane> 

Answer 1

Проблема заключается в том, что getClassesList возвращает ResultSet, который уже закрыт:

try { 
    rs = connection.createStatement().executeQuery(query); 
    newConnection.shutdown(); // why shut down the connection when you plan to work on rs? 
    rs.close(); // same question applies here 
    return rs; 
} 

Но в вашем AdmissionController вы хотите работать с ResultSet:

ResultSet rs = newSelectClassesQuery.GetClassesList(query); // already closed! 
totalClasses = FXCollections.observableArrayList(); 
while(rs.next()) // exception 
{ 
    // AvailableClasses classesData = new AvailableClasses(); 
    classBox.getItems().add(rs.getString("class_name")); 
} 
rs.close(); 

---

Подсказка: реорганизовать классы ;-)

Если вы спросите меня, вы должны рассмотреть вопрос о создании объектов DAO, которые получают и возвращают классы из базы данных. Тогда ваш код пользовательского интерфейса не должен знать о жизненном цикле ResultSet.