Modular Java 13 / JavaFx WebWiew fails to display when jlinked

Question

I have a problem with displaying a webpage in an embedded window but only when creating a standalone jlinked package and only for certain https sites.

I followed the instructions at https://openjfx.io/openjfx-docs/#install-javafx for creating a simple modular App and this works fine when run from the command line with

java --module-path "%PATH_TO_FX%;mods" -m uk.co.comsci.testproj/uk.co.comsci.testproj.Launcher

but after jlinking with the command

jlink --module-path "%PATH_TO_FX_MODS%;mods" --add-modules uk.co.comsci.testproj --output launch

and running with

launch\bin\java.exe -m uk.co.comsci.testproj/uk.co.comsci.testproj.Launcher

the javaFx scene opens but just a blank screen... and I have to use task manager to terminate the App.

If I change the URL to other https sites, it displays fine.

I guess it is down to the security settings and policies somewhere but I have no idea where to start.

I have tried monitoring with WireShark and this shows that when run from java and it works it does some TLSv1.3 stuff to establish the connection. When run as a jlinked package it only does TLSv1.2 stuff. Maybe a clue?

Here's my SSCE:

module-info.java

module uk.co.comsci.testproj {
    requires javafx.web;
    requires javafx.controls;
    requires javafx.media;
    requires javafx.graphics;
    requires javafx.base;
    exports uk.co.comsci.testproj;
}

Launcher.java

package uk.co.comsci.testproj;

public class Launcher {
    public static void main(String[] args) {
        try {
            MainApp.main(args);
        } catch (Exception ex) {
            System.err.println("Exception!!! " + ex);
        }
    }
}

MainApp.java

package uk.co.comsci.testproj;

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Modality;
import javafx.stage.Stage;
import javafx.stage.StageStyle;

public class MainApp extends Application {

    private Stage mainStage;

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

    @Override
    public void start(final Stage initStage) throws Exception {

        mainStage = new Stage(StageStyle.DECORATED);

        mainStage.setTitle("Test Project");

        WebView browser = new WebView();
        WebEngine webEngine = browser.getEngine();

//        webEngine.load("https://app.comsci.co.uk"); // url);
        String uri = "https://test-api.service.hmrc.gov.uk/oauth/authorize"
                + "?response_type=code&redirect_uri=http%3A%2F%2Flocalhost%3A8084%2Fredirect"
                + "&state=lFuLG42uri_aAQ_bDBa9TZGGYD0BDKtFRv8xEaKbeQo"
                + "&client_id=tASN6IpBPt5OcIHlWzkaLXTAyMEa&scope=read%3Avat+write%3Avat";
        webEngine.load(uri);

        Button closeButt = new Button("Cancel");
        closeButt.setOnMouseClicked(event -> {
            mainStage.close();
        });
        HBox closeButBar = new HBox(closeButt);
        closeButBar.setAlignment(Pos.BASELINE_RIGHT);

        VBox vlo = new VBox(browser, closeButBar);
        vlo.setFillWidth(true);
        vlo.setSpacing(10.0);
        VBox.setVgrow(browser, Priority.ALWAYS);

        Scene scene2 = new Scene(vlo, 800, 800);
        mainStage.setScene(scene2);
        mainStage.initModality(Modality.APPLICATION_MODAL);
        mainStage.setTitle("Test connection");
        mainStage.showAndWait();
    }

}

Any help much appreciated.

Comsci · Accepted Answer · 2020-02-06 10:27:13Z

6

OK. Finally tracked it down. So in case anyone has the same problem:

Nothing to do with JavaFx or Webview it was the TLS handshake failing.

Replacing the webview with an http client get

            String uri = "https://test-api.service.hmrc.gov.uk/oauth/authorize"
                    + "?response_type=code&redirect_uri=http%3A%2F%2Flocalhost%3A8084%2Fredirect"
                    + "&state=lFuLG42uri_aAQ_bDBa9TZGGYD0BDKtFRv8xEaKbeQo"
                    + "&client_id=tASN6IpBPt5OcIHlWzkaLXTAyMEa&scope=read%3Avat+write%3Avat";

            var client = HttpClient.newHttpClient();
            var request = HttpRequest.newBuilder()
                    .GET()
                    .uri(URI.create(uri))
                    .timeout(Duration.ofSeconds(15))
                    .build();

            try {
                HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
                System.out.println("REsponse  " + response.body());
            } catch (IOException | InterruptedException e) {
                e.printStackTrace();
            }

and running with '-Djavax.net.debug=ssl:handshake:verbose' showed that the handshake was failing. running the embedded keytool -showinfo -tls and comparing this with the system keytool output showed that the TLS_ECDHE_... cyphers where not supported in the jlinked output

A bit of googling and help from here https://www.gubatron.com/blog/2019/04/25/solving-received-fatal-alert-handshake_failure-error-when-performing-https-connections-on-a-custom-made-jre-with-jlink/ showed that all I needed to do was add

requires jdk.crypto.cryptoki;

to my module-info.java :-)

answered Feb 6, 2020 at 10:27

Comsci

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2 Comments

Rik Over a year ago

Great stuff! I was getting all kinds of odd behaviour from the WebView in my jlinked app (missing images/fonts/styles/etc) until I came across this answer!

Leons Over a year ago

Worked like a charm. The answer is really helpful. Was banging my head for couple of days in this issue. Thanks a lot @Comsci

Yeshwin Verma · Accepted Answer · 2021-06-16 06:25:15Z

0

You need to just add the following line in module-info.java

requires jdk.crypto.cryptoki;

answered Jun 16, 2021 at 6:25

Yeshwin Verma

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