Bug ID: JDK-8161293 NPE while closing pop up window

Type: Bug
Component: javafx
Sub-Component: web
Affected Version: 8,9
Priority: P3
Status: Closed
Resolution: Not an Issue
Submitted: 2016-07-13
Updated: 2016-07-15
Resolved: 2016-07-15
JDK 9
9Resolved
---------- BEGIN SOURCE ---------- 
test.html 
====== 

<!DOCTYPE HTML> 
<html> 
<head> 
    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> 
</head> 
<body> 
<div style="position:relative"> 
<h2>Controls</h2> 
<button onclick="simulateRealTimeUpdates()">Start simulation</button> 
<button onclick="stopRealtime()">Stop simulation</button> 
<button onclick="openNewWindow()">Open new window</button> 
</div> 

<script> 
    function simulateRealTimeUpdates() { 
        window.service.data({ 
            callback: function(dataStr) { 
                dataStr = null; 
            } 
        }); 
    } 

    function openNewWindow() { 
        window.open('grid.html'); 
    } 

    function stopRealtime() { 
        window.service.cancelTimer(); 
    } 
</script> 
</body> 
</html> 

MemoryLeak2Service.java 
===================== 

package memoryLeak2; 

import javafx.application.Platform; 
import netscape.javascript.JSObject; 

import java.util.Arrays; 
import java.util.Timer; 
import java.util.TimerTask; 

public class MemoryLeak2Service { 
    private final Timer timer = new java.util.Timer(); 
    private final int size = 1000000; 
    private final String strBuffer; 
    //private final char[] chrBuffer; 
     
    public MemoryLeak2Service() 
    { 
    	StringBuffer buffer = new StringBuffer(size); 
    	for (int i = 0; i < size; i++){ 
    	buffer.append("A"); 
     	} 
    	
    	strBuffer = buffer.toString(); 
    	//chrBuffer = strBuffer.toCharArray(); 
    } 
     
    public void data(JSObject cb) { 
        TimerTask tt = new TimerTask() { 
            public void run() { 
                Platform.runLater(new Runnable() { 
                    @Override 
                    public void run() { 
                    	// strBuffer - LEAKS, chrBuffer isn't leaking. 
                    	cb.call("callback", strBuffer); 
                    	//cb.call("callback", chrBuffer); 
                    } 
                }); 
            } 
        }; 
        timer.schedule(tt, 1000, 100); 
    } 

    /** 
     * Cancel timer 
     */ 
    public void cancelTimer() { 
        timer.cancel(); 
        timer.purge(); 

    } 
} 

MemoryLeak2.java 
=============== 

package memoryLeak2; 

import javafx.application.Application; 
import javafx.beans.value.ChangeListener; 
import javafx.beans.value.ObservableValue; 
import javafx.concurrent.Worker.State; 
import javafx.event.EventHandler; 
import javafx.geometry.HPos; 
import javafx.geometry.VPos; 
import javafx.scene.Scene; 
import javafx.scene.layout.Region; 
import javafx.scene.paint.Color; 
import javafx.scene.web.PopupFeatures; 
import javafx.scene.web.WebEngine; 
import javafx.scene.web.WebEvent; 
import javafx.scene.web.WebView; 
import javafx.stage.Stage; 
import javafx.stage.WindowEvent; 
import javafx.util.Callback; 
import netscape.javascript.JSObject; 

public class MemoryLeak2 extends Application { 

    public static final int WIDTH = 1000; 
    public static final int HEIGHT = 600; 

    @Override 
    public void start(Stage stage) { 
        create(stage); 
    } 

    public static void create(Stage stage) { 
        // create the scene 
        stage.setTitle("Original Web View"); 
        Scene scene = new Scene(new Browser(), WIDTH, HEIGHT, Color.web("#666970")); 
        stage.setScene(scene); 
        stage.show(); 


        stage.addEventHandler(WindowEvent.WINDOW_CLOSE_REQUEST, new EventHandler<WindowEvent>() { 

            @Override 
            public void handle(WindowEvent event) { 
                //Exit the application on first window close 
                System.exit(0); 
            } 

        }); 



    } 

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

} 

class Browser extends Region { 

    /** 
     * html file to load 
     */ 
    private String fileToLoad = "test.html"; 
    final WebView browser = new WebView(); 
    final WebEngine webEngine = browser.getEngine(); 
    private MemoryLeak2Service myService; 

    public Browser() { 
        //apply the styles 
        getStyleClass().add("browser"); 



        webEngine.getLoadWorker().stateProperty().addListener(new ChangeListener<State>() { 

            @Override 
            public void changed(ObservableValue<? extends State> stateParam, State oldState, State newState) { 

                switch (newState) { 
                case READY: 
                    break; 
                case SCHEDULED: 
                    break; 

                case RUNNING: 
                    break; 

                case CANCELLED: 
                    break; 

                case SUCCEEDED: 
                    if(!"about:blank".equals(webEngine.getLocation())) { 
                        final JSObject window = (JSObject) webEngine.executeScript("window"); 
                        myService = new MemoryLeak2Service(); 
                        //set service as widow member 
                        window.setMember("service", myService); 
                        window.call("init"); 
                    } 
                    break; 

                default: 
                    break; 
                } 
            } 
        }); 

        //alert to display some javascript logs 
        webEngine.setOnAlert(new EventHandler<WebEvent<String>>() { 

            @Override 
            public void handle(WebEvent<String> webEvent) { 
                System.out.println(webEvent.getData()); 
            } 

        }); 

        // load the web page 
        webEngine.load(Browser.class.getResource(fileToLoad).toExternalForm()); 

        getChildren().add(browser); 
        webEngine.setCreatePopupHandler(new Callback<PopupFeatures, WebEngine>() { 
            @Override 
            public WebEngine call(PopupFeatures param) { 
                Stage stg = new Stage(); 
                stg.setTitle("Popup View"); 
                final Browser root = new Browser(); 
                Scene scene = new Scene(root, 800, 800, Color.web("#666970")); 
                stg.setScene(scene); 
                stg.show(); 
                stg.addEventHandler(WindowEvent.WINDOW_CLOSE_REQUEST, new EventHandler<WindowEvent>() { 

                    @Override 
                    public void handle(WindowEvent event) { 
                        if(root != null) { 
                            //On close cancel te timer 
                            root.getMyService().cancelTimer(); 
                            //load null to free some memory 
                            root.getWebEngine().load(null); 
                        } 
                    } 

                }); 

                return root.getWebEngine(); 
            } 
        }); 
    } 

    public WebEngine getWebEngine() { 
        return webEngine; 
    } 

    public MemoryLeak2Service getMyService() { 
        return myService; 
    } 

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

    @Override protected double computePrefWidth(double height) { 
        return MemoryLeak2.HEIGHT; 
    } 

    @Override protected double computePrefHeight(double width) { 
        return MemoryLeak2.WIDTH; 
    } 
} 


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

When we try to close the pop up window, below NPE observed:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
        at Browser$3$1.handle(MemoryLeak2.java:140)
        at Browser$3$1.handle(MemoryLeak2.java:134)
        at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
        at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
        at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
        at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
        at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
        at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
        at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
        at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
        at javafx.event.Event.fireEvent(Event.java:198)
        at com.sun.javafx.stage.WindowPeerListener.closing(WindowPeerListener.java:93)
        at com.sun.javafx.tk.quantum.GlassWindowEventHandler.run(GlassWindowEventHandler.java:146)
        at com.sun.javafx.tk.quantum.GlassWindowEventHandler.run(GlassWindowEventHandler.java:40)
        at java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.tk.quantum.GlassWindowEventHandler.lambda$handleWindowEvent$4(GlassWindowEventHandler.java:175)
        at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
        at com.sun.javafx.tk.quantum.GlassWindowEventHandler.handleWindowEvent(GlassWindowEventHandler.java:173)
        at com.sun.glass.ui.Window.handleWindowEvent(Window.java:1313)
        at com.sun.glass.ui.Window.notifyClose(Window.java:1213)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:189)
        at java.lang.Thread.run(Thread.java:804)
NPE is due to app issue... In test.html, we need to replace window.open('grid.html'); with window.open('test.html'); Hence closing this issue.
15-07-2016
Currently checking whether NPE is due to app issue or not..
13-07-2016