FULL PRODUCT VERSION :
java version "1.8.0_121"

ADDITIONAL OS VERSION INFORMATION :
Linux XPS-15-9560 4.8.0-49-generic #52~16.04.1-Ubuntu SMP Thu Apr 20 10:55:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
Calling Desktop.mail(new URI("mailto:" + ...) hangs. Nothing happens. There is no mail client installed on my system (Ubuntu 16.04).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the code below

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Should get an Exception indicating that no mail client is installed on the system.
ACTUAL -
Application hangs.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package app;

import java.awt.Desktop;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class OpenDefaultBrowser extends Application {

@Override
public void start(Stage primaryStage) {
final HBox root = new HBox(5);
final TextField textField = new TextField("help@example.com");
final Button goButton = new Button("Mail");

EventHandler<ActionEvent> goHandler = new EventHandler<ActionEvent>() {

public void handle(ActionEvent event) {

if (Desktop.isDesktopSupported()) {
try {
Desktop desktop = Desktop.getDesktop();
if (desktop.isSupported(Desktop.Action.MAIL)) {
desktop.mail(new URI("mailto:" + textField.getText() + "?subject=Hello%20World"));
} else {
System.out.println("e-mail not supported");
}
} catch (IOException | URISyntaxException ioe) {
ioe.printStackTrace();
}
} else {
System.out.println("Desktop not supported");
}

}

};

textField.setOnAction(goHandler);
goButton.setOnAction(goHandler);

root.getChildren().addAll(textField, goButton);
final Scene scene = new Scene(root, 250, 150);
primaryStage.setScene(scene);
primaryStage.show();
}

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