WebView webViev = new WebView();
     
        webViev.getEngine().load("https://www.babilon-t.com/");
        webViev.setPrefSize(200,150);
     


        primaryStage.setScene(new Scene (webViev));
        primaryStage.show();

package com.company;


import javafx.application.Application;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

import java.io.PrintWriter;

public class Main extends Application {



    public static void main(String[] args) {

launch(args);


    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        System.setProperty("http.proxyHost", "62.173.145.48");
        System.setProperty("http.proxyPort", "3128");
        WebView webViev = new WebView();
      
        webViev.getEngine().load("https://www.babilon-t.com/");
        webViev.setPrefSize(200,150);
     


        primaryStage.setScene(new Scene (webViev));
        primaryStage.show();






    }
}

  

You should use

System.setProperty("http.proxyHost","your proxy address");
System.setProperty("http.proxyPort","your port");

for http sites and

System.setProperty("https.proxyHost","your proxy address");
System.setProperty("https.proxyPort","your port");

for https sites