exception error java fx

good morning, I'm working on a code, make the connection, built the user class, and everything else, but at the time of executing it I have this error which is in the FXMLOADER, here I leave the code of controlador :

package application;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import java.util.ResourceBundle;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;

import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.*;

import javafx.scene.control.cell.PropertyValueFactory;



public class Controlador implements Initializable{

    ObservableList <Usuario> data =FXCollections.observableArrayList();
   @FXML TableView<Usuario>  tablacliente;
   @FXML TableColumn<Usuario, String> nombrescol;
   @FXML TableColumn<Usuario,String > apellidoscol;
   @FXML TableColumn<Usuario, Integer>  clienteid;
   @FXML private Button add;
   @FXML private Button show;
   PreparedStatement preparedStatement=null;
   ResultSet rs=null;
   Connection Conexion=null;
   @FXML  private TextField nm;
    @FXML private TextField ap;
    @FXML private Button agregar;

@Override
public void initialize(URL arg0, ResourceBundle arg1) {
    clienteid.setCellValueFactory(new PropertyValueFactory <Usuario, Integer>("id_cliente"));
    nombrescol.setCellValueFactory(new PropertyValueFactory <Usuario, String>("nombres"));
     apellidoscol.setCellValueFactory(new PropertyValueFactory <Usuario, String>("apellidos"));
    agregar();
}

public void conexion(){

    String query="select * from cliente";
    try {
        Conexion=DriverManager.getConnection("jdbc:sqlserver://DESKTOP-4JA6SFR:1433;databaseName=prueba", "sa", "123");
        preparedStatement=Conexion.prepareStatement(query);
        rs=preparedStatement.executeQuery(query);

        while ( rs.next() ) 
        {
        data.add(new Usuario(
                rs.getString("nombre"),
                rs.getString("apellido"),
                rs.getInt("id")
                ));
        tablacliente.setItems(data);
        }

        preparedStatement.close();
        rs.close();

        } 

    catch (SQLException e) {
         e.printStackTrace();
     }
     if(Conexion!=null) {
         System.out.println("conexion exitosa");

     }

}

public void agregar() {
 String Nombre=nm.getText();
 String Apellido=ap.getText();
 String query="INSERT INTO CLIENTE (nombre,apellido)VALUES (?,?)";

 preparedStatement=null;

 try
 {
     preparedStatement=Conexion.prepareStatement(query);
     preparedStatement.setString(1, Nombre);
     preparedStatement.setString(2, Apellido);

 }
 catch (SQLException e) {
     e.printStackTrace();
 }
 finally {
     try {
        preparedStatement.execute(query);
    } catch (SQLException e) {

        e.printStackTrace();
    }
     try {
        preparedStatement.close();
    } catch (SQLException e) {

        e.printStackTrace();
    }
 }
   nm.clear();
   ap.clear();
   conexion();


}
}

code FXML

<?import application.Usuario.*?>

<?import application.Controlador.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.Controlador">
   <children>
      <AnchorPane layoutY="-11.0" prefHeight="527.0" prefWidth="855.0">
         <children>
            <TextField fx:id="nm" layoutX="175.0" layoutY="103.0" />
            <TextField fx:id="ap" layoutX="175.0" layoutY="176.0" prefHeight="25.0" prefWidth="149.0" />
            <Label layoutX="50.0" layoutY="107.0" prefHeight="17.0" prefWidth="107.0" text="NOMBRES" />
            <Label layoutX="50.0" layoutY="180.0" text="APELLIDOS" />
            <TableView layoutX="344.0" layoutY="54.0" prefHeight="397.0" prefWidth="488.0">
              <columns>
                <TableColumn fx:id="clienteid" prefWidth="181.0" text="ID" />
                <TableColumn fx:id="nombrescol" prefWidth="140.0" text="NOMBRES" />
                  <TableColumn fx:id="apellidoscol" prefWidth="140.0" text="APELLIDOS" />
              </columns>
            </TableView>
            <Button fx:id="agregar" layoutX="65.0" layoutY="264.0" mnemonicParsing="false" onAction="#agregar" prefHeight="25.0" prefWidth="149.0" text="AGREGAR" />
         </children>
      </AnchorPane>
   </children>
</AnchorPane>

and the code of main

package application;

import java.io.IOException;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.paint.Color;


public class Main extends Application {
    @Override
    public void start(Stage stage) {
         stage.setTitle("ARGUS V1.0 ");
         Parent root = null;
         try {
         root = FXMLLoader.load(getClass().getResource("Datos.fxml"));
         } catch (IOException e) {
         e.printStackTrace();
         }
         Scene scene = new Scene(root,  Color.WHITE);
         stage.setScene(scene);
         stage.show();
         }

    public static void main(String[] args) {
        launch(args);
    }
}

class code of usuario

package application;

import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

public class Usuario {



    private StringProperty nombres;
    private StringProperty apellidos;
    private IntegerProperty id_cliente;

public Usuario ( String nombres, String apellidos, Integer id_cliente) {
    this.nombres=  new SimpleStringProperty (nombres);
    this.apellidos= new SimpleStringProperty ( apellidos);
    this.id_cliente=new SimpleIntegerProperty (id_cliente);
}


public String getNombres() {
    return nombres.get();
}

public  void  setNombres(String nombres) {
    this.nombres=new SimpleStringProperty (nombres);
}



public String getApellidos() {
    return apellidos.get();
}


public  void  setApellidos(String apellidos) {
    this.apellidos=new SimpleStringProperty ( apellidos);
}



public Integer getId_cliente() {
    return id_cliente.get();
}



public  void  setid_cliente(Integer id_cliente) {
    this.id_cliente=new SimpleIntegerProperty (id_cliente);
}

}

the errors

javafx.fxml.LoadException: 
/C:/Users/Soporte/eclipse-workspace/ProyectoArgus/bin/application/Datos.fxml

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at application.Main.start(Main.java:19)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
    at application.Controlador.agregar(Controlador.java:98)
    at application.Controlador.initialize(Controlador.java:43)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
    ... 17 more
Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Root cannot be null
    at javafx.scene.Scene.<init>(Scene.java:336)
    at javafx.scene.Scene.<init>(Scene.java:235)
    at application.Main.start(Main.java:23)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    ... 1 more
Exception running application application.Main