yeFULL PRODUCT VERSION :
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b18, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
MS windows7 6.1 Build 7601 SP1

A DESCRIPTION OF THE PROBLEM :
WebKit browser isn't able to launch pdf.js document viewer any more after upgrage from jdk 1.8 51 -> 66. No easy way to find out the reason. The only js debugger which may work with WebView is firebug lite, but it has no breakpoint/step in/out support. Console log doen't show any crashes. PDF document arrives to the js virtual machine, but rendeing fails.

REGRESSION.  Last worked in version 8u51

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Install netbeans with JavaFX support
2. install jdk 1.8 u66
3. open sample https://docs.oracle.com/javase/8/javafx/sample-apps/WebViewSample.zip in netbeans
4. replace url in the source of the sample at line 228 from oracle website to https://mozilla.github.io/pdf.js/web/viewer.html
5. launch the application

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
viewer should show pdf
ACTUAL -
viewer doesn't show pdf file

ERROR MESSAGES/STACK TRACES THAT OCCUR :
No crashes available. js console doesn't have any messages.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/*
 * Copyright (c) 2011, 2014, Oracle and/or its affiliates.
 * All rights reserved. Use is subject to license terms.
 *
 * This file is available and licensed under the following license:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *  - Neither the name of Oracle nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package webviewsample;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.value.ObservableValue;
import javafx.collections.ListChangeListener.Change;
import javafx.concurrent.Worker.State;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.geometry.HPos;
import javafx.geometry.Pos;
import javafx.geometry.VPos;
import javafx.print.PrinterJob;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.Hyperlink;
import javafx.scene.control.MenuItem;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.Region;
import javafx.scene.paint.Color;
import javafx.scene.web.PopupFeatures;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebHistory;
import javafx.scene.web.WebHistory.Entry;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
import netscape.javascript.JSObject;

public class WebViewSample extends Application {

    private Scene scene;

    @Override
    public void start(Stage stage) {
        // create scene
        stage.setTitle("Web View Sample");
        scene = new Scene(new Browser(stage), 900, 600, Color.web("#666970"));
        stage.setScene(scene);
        // apply CSS style
        scene.getStylesheets().add("webviewsample/BrowserToolbar.css");
        // show stage
        stage.show();
    }

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

class Browser extends Region {

    private final HBox toolBar;
    final private static String[] imageFiles = new String[]{
        "product.png",
        "blog.png",
        "documentation.png",
        "partners.png",
        "help.png"
    };
    final private static String[] captions = new String[]{
        "Products",
        "Blogs",
        "Documentation",
        "Partners",
        "Help"
    };
    final private static String[] urls = new String[]{
        "http://www.oracle.com/products/index.html",
        "http://blogs.oracle.com/",
        "http://docs.oracle.com/javase/index.html",
        "http://www.oracle.com/partners/index.html",
        WebViewSample.class.getResource("help.html").toExternalForm()
    };
    final ImageView selectedImage = new ImageView();
    final Hyperlink[] hpls = new Hyperlink[captions.length];
    final Image[] images = new Image[imageFiles.length];
    final WebView browser = new WebView();
    final WebEngine webEngine = browser.getEngine();
    final Button toggleHelpTopics = new Button("Toggle Help Topics");
    final WebView smallView = new WebView();
    final ComboBox comboBox = new ComboBox();
    private boolean needDocumentationButton = false;
    
    
    public Browser(final Stage stage) {
        //apply the styles
        getStyleClass().add("browser");
                
        for (int i = 0; i < captions.length; i++) {
            // create hyperlinks
            Hyperlink hpl = hpls[i] = new Hyperlink(captions[i]);
            Image image = images[i]
                    = new Image(getClass().getResourceAsStream(imageFiles[i]));
            hpl.setGraphic(new ImageView(image));
            final String url = urls[i];
            final boolean addButton = (hpl.getText().equals("Help"));  
            
            // process event 
            hpl.setOnAction((ActionEvent e) -> {
                needDocumentationButton = addButton;
                webEngine.load(url);
            });
                    
        }


        comboBox.setPrefWidth(60);

        // create the toolbar
        toolBar = new HBox();
        toolBar.setAlignment(Pos.CENTER);
        toolBar.getStyleClass().add("browser-toolbar");
        toolBar.getChildren().add(comboBox);
        toolBar.getChildren().addAll(hpls);
        toolBar.getChildren().add(createSpacer());

        //set action for the button
        toggleHelpTopics.setOnAction((ActionEvent t) -> {
            webEngine.executeScript("toggle_visibility('help_topics')");
        });

        smallView.setPrefSize(120, 80);

        //handle popup windows
        webEngine.setCreatePopupHandler(
                (PopupFeatures config) -> {
                    smallView.setFontScale(0.8);
                    if (!toolBar.getChildren().contains(smallView)) {
                        toolBar.getChildren().add(smallView);
                    }
                    return smallView.getEngine();
        });

        //process history
        final WebHistory history = webEngine.getHistory();
        history.getEntries().addListener(
            (Change<? extends Entry> c) -> {
                c.next();
                c.getRemoved().stream().forEach((e) -> {
                comboBox.getItems().remove(e.getUrl());
            });
                c.getAddedSubList().stream().forEach((e) -> {
                comboBox.getItems().add(e.getUrl());
            });
        });

        //set the behavior for the history combobox               
        comboBox.setOnAction((Event ev) -> {
            int offset
                    = comboBox.getSelectionModel().getSelectedIndex()
                    - history.getCurrentIndex();
            history.go(offset);
        });

        // process page loading
        webEngine.getLoadWorker().stateProperty().addListener(
            (ObservableValue<? extends State> ov, State oldState, 
                State newState) -> {
                    toolBar.getChildren().remove(toggleHelpTopics);
                    if (newState == State.SUCCEEDED) {
                        JSObject win
                                = (JSObject) webEngine.executeScript("window");
                        win.setMember("app", new JavaApp());
                        if (needDocumentationButton) {
                            toolBar.getChildren().add(toggleHelpTopics);
                        }
                    }
        });
        //adding context menu
        final ContextMenu cm = new ContextMenu();
        MenuItem cmItem1 = new MenuItem("Print");
        cm.getItems().add(cmItem1);
        toolBar.addEventHandler(MouseEvent.MOUSE_CLICKED, (MouseEvent e) -> {
            if (e.getButton() == MouseButton.SECONDARY) {
                cm.show(toolBar, e.getScreenX(), e.getScreenY());
            }
        });

        //processing print job
        cmItem1.setOnAction((ActionEvent e) -> {
            PrinterJob job = PrinterJob.createPrinterJob();
            if (job != null) {
                webEngine.print(job);
                job.endJob();
            }
        });

        // load the home page        
        webEngine.load("https://mozilla.github.io/pdf.js/web/viewer.html");

        //add components
        getChildren().add(toolBar);
        getChildren().add(browser);
    }

    // JavaScript interface object
    public class JavaApp {

        public void exit() {
            Platform.exit();
        }
    }

    private Node createSpacer() {
        Region spacer = new Region();
        HBox.setHgrow(spacer, Priority.ALWAYS);
        return spacer;
    }

    @Override
    protected void layoutChildren() {
        double w = getWidth();
        double h = getHeight();
        double tbHeight = toolBar.prefHeight(w);
        layoutInArea(browser,0,0,w,h-tbHeight,0,HPos.CENTER,VPos.CENTER);
        layoutInArea(toolBar,0,h-tbHeight,w,tbHeight,0,HPos.CENTER,VPos.CENTER);
    }

    @Override
    protected double computePrefWidth(double height) {
        return 900;
    }

    @Override
    protected double computePrefHeight(double width) {
        return 600;
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Rollback to jdk 1.8 51u