JavaFX 13 Webview hangs

Guru guru.hb at
Thu Feb 13 03:47:52 UTC 2020

Hi Lior,

Could you share a simplified test application with the html content or web content which leads to “webview frame comes up empty” so that I can test and debug at my end.


> On 11-Feb-2020, at 8:51 PM, Lior Yaffe <lior.yaffe at> wrote:
> Test results:
> OpenJFX 11 never hangs
> OpenJFX 13 always hangs
> OpenJFX 15ea the webview frame comes up empty but the runtime never hangs
> The Java version has no effect.
> The hang seems to occur in native code since there is no way to take a thread dump using jstack and the only possible action is to kill the process.
> Is there any other logging or diagnostic you can suggest? 
> February 10, 2020 7:24:54 PM CET Kevin Rushforth <kevin.rushforth at> wrote:    Can you also try JDK 11 with OpenJFX 13? I suspect it will not make    a difference (i.e., it will still hang), but it would be good to    confirm. And even more interesting will be the results of JavaFX    15-ea.
>    Thanks.
>    -- Kevin
> On 2/10/2020 10:17 AM, Lior Yaffe      wrote:
> The problem does not reproduce when using JavaFX        11 regardless of the version of Java being used.        
> I will try with Java 15ea
> On Mon, Feb 10, 2020, 17:01          Kevin Rushforth <kevin.rushforth at>          wrote:
>        And one last          thing to try: can you run it with the JavaFX 15-ea+1 build 
>          and see if that makes a difference?
>          -- Kevin
>          On 2/10/2020 6:59 AM, Kevin Rushforth wrote:
>> Seems I missed your comment about it being hung to the          point you can't 
>> run jstack.
>> If you are using JDK 12 or later, you might try with JDK          11 and see if 
>> that makes a difference. It will help narrow it down to a          change in 
>> the JDK versus a change in JavaFX (although I suspect          it's a change in 
>> JavaFX).
>> -- Kevin
>> On 2/10/2020 6:40 AM, Kevin Rushforth wrote:
>>> A thread stack dump using "jstack" might be helpful.
>>> Also, what version of the JDK are you running?
>>> -- Kevin
>>> On 2/9/2020 4:07 AM, Lior Yaffe wrote:
>>>> My application is a Java application running a          Javascript/Html website
>>>> inside a JavaFX WebView. It was working stable          for several years with
>>>> various versions of Java and JavaFX.
>>>> As far as I can tell it is following best coding          practices such as 
>>>> running
>>>> all UI code in the JavaFX thread and as such.
>>>> Since upgrading to JavaFX 13 my application hangs          sporadically. When it
>>>> happens the website running inside the webview          becomes unresponsive and
>>>> displays an hourglass icon.
>>>> When the app hangs I cannot take a thread dump          using jstack or close 
>>>> the
>>>> application. I have to kill it.
>>>> The problem is reproduced on multiple Windows          workstations. It was 
>>>> never
>>>> reported or reproduced on Linux or Mac so there          is a chance it is 
>>>> Windows
>>>> specific.
>>>> When the app hangs the CPU is ideal so this is          not a busy loop.
>>>> Which diagnostic information can I obtain to          better understand this 
>>>> problem?

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