updated Main.java

package application;


import java.io.IOException;
import java.io.OutputStream;

import cern.jet.random.Normal;
import javafx.application.Application;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.RadioButton;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.event.EventHandler;



public class Main extends Application  {

    @FXML
    private static RadioButton callBox1;

    @FXML
    private static RadioButton putBox1;

    @FXML
    private static TextField inputCSP;

    @FXML
    private static TextField inputEP;

    @FXML
    private static TextField inputRFIR;

    @FXML
    private static TextField inputTUE;

    @FXML
    private static TextField inputV;

    @FXML
    private Button calculatebtn;

    @FXML
    private static String output;

    @FXML
    private static TextField outputarea;

    @Override
    public void start(Stage primaryStage) throws Exception {


    Parent root = FXMLLoader.load(getClass().getResource("/application/GUI.fxml"));
    Scene scene = new Scene(root,640,400);
    primaryStage.setResizable(false);
    primaryStage.setScene(scene);
    primaryStage.show();
    primaryStage.setTitle("Black-Scholes Pricer (European Options)");
        }



    public static void maths(String[] args) {

        System.out.println("hi");

        Normal a = new Normal(0,1, null);

        Double s= Double.parseDouble(inputCSP.getText());

        Double e = Double.parseDouble(inputEP.getText());

        Double risk = Double.parseDouble(inputRFIR.getText());
        Double r2 = (risk/100);

        Double time = Double.parseDouble(inputTUE.getText());
        Double t2 = (time/365);

        Double volatility = Double.parseDouble(inputV.getText());
        Double v2 = (volatility/100);

     // Calculation of d1
        Double t = Math.log(s/e) + (r2 + 0.5*Math.pow(v2, 2))*t2;
        Double b = v2*Math.sqrt(t2);
        Double d1 = t/b;

        // Calculation of d2
        double root = Math.pow(t2, 0.5);
        double d2 = d1 - (v2*root);

        // Rounding d1 and d2 to 2 decimal places for use in normal distribution

        double roundedd1 = Math.round(d1*100)/100.0;
        double roundedd2 = Math.round(d2 *100)/100.0;

        double cumulatived1 = a.cdf(roundedd1);
        double cumulatived2 = a.cdf(roundedd2);

        double roundc1 = Math.round(cumulatived1*10000)/10000.0;
        double roundc2 = Math.round(cumulatived2*10000)/10000.0;

        //Use of final formula

        double e2 = Math.E;
        double value = (s*roundc1) - (((e/Math.pow(e2, r2*t2))*roundc2));

        double value2 = Math.round(value*1000)/1000.0;

        //calculating the put

        double value3 = (value2 + (e/Math.pow(e2, r2*t2)) - s);

        String valuecall = String.valueOf(value2);
        String valueput = String.valueOf(value3);

        if(callBox1.isSelected()) output=valuecall;
        if(putBox1.isSelected()) output=valueput;

        outputarea.setText(output);
        }





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