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Re: [platform-swt-dev] SWT browser

Hi Dermot, sorry for the late reply,

I've confirmed that enabling applets in the Cocoa-based Browser with the Java Plug-in set to launch applets in a separate process still crashes.  I've logged https://bugs.eclipse.org/bugs/show_bug.cgi?id=337456 for investigating this, since with the new Java Plug-in there is at least the hope that this may be possible.  Interestingly, though not really helpful, I notice that the Java plug-in now detects the case of being loaded in the same process as a running JRE and no longer crashes, it just aborts its load.

I've logged https://bugs.eclipse.org/bugs/show_bug.cgi?id=337455 for the case of displaying applets in WebKit-based Browsers on Windows.  As the FAQ mentions, applets do work with IE- and XULRunner-based Browsers on Windows, but it's also worth noting that there are minimal required versions for these renderers (ie.- launching applets in a separate process is not sufficient, some support is needed from the native renderer as well).

Yes, http://www.eclipse.org/swt/faq.php#howbuildjar describes what you need to build the swt jar.  Also possibly useful, http://www.eclipse.org/swt/faq.php#howbuildplugin describes how to use an export wizard to create the swt eclipse plug-in.  If your experiments create any feedback for enabling applets in these contexts then please add your comments to the bug reports linked above, thanks!

Grant




"Dermot Doherty" <dermot@xxxxxxxxxxx>
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11/02/2011 02:47 PM

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Re: [platform-swt-dev] SWT browser





Thanks Grant.
 
Okay, I will produce some snippets that can evidence these issues, and file any relevant bugs.
 
#4 & #5 - SWT WebKit Browser running Java applets - Okay, I see that FAQ about running Java applets on Mac and the JVMs colliding. From what Scott said yesterday, could this FAQ point be in place from Mac Carbon which could also mean that this was an issue with the older Mac Java plugin. From my experience, the New Java Plugin2 is much more stable and you can specify to run applets in their own process in Java Preferences. The rule about applets is that if the codebase is the same, applets will get loaded in the same JVM. There is also a new parameter "separate_jvm" which allows a programmer to request a separate JVM. With these tools at hand, it may be possible for the developer to avert the issue described in this FAQ on Mac... if it is even still happening on the new Mac Cocoa WebKit using the New Java Plugin2.
I also see that Java is being disabled on Windows SWT WebKit. This may be unnecesary on Windows who seems to have no problem with JVMs launching other JVMs.
Anyways, I would like to be able to test this and provide some feedback. I understand that I would have to build the SWT jar, removing the line of code that disables Java. Is the FAQ http://www.eclipse.org/swt/faq.php#howbuildjar where I go to start this process?
 
Dermot
 
----- Original Message -----
From: Grant Gayed
To: Eclipse Platform SWT component developers list.
Sent: Friday, February 11, 2011 9:35 AM
Subject: Re: [platform-swt-dev] SWT browser


Hi Dermot,

#1 - I don't see this, but our cases may be different.  Behaviours like this should be consistent across the Browser implementations, so please log a report for this and provide a means of reproducing the error.  You can probably just use http://dev.eclipse.org/viewcvs/viewvc.cgi/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet128.java?view=co and specify a specific url to navigate to initially.

#2 - Like Scott said, this is very strange.  If you are able to make a reproducible case of it then please log a bug.  Without a case that can be reproduced here it will be impossible to fix this, as I've never heard of it before.

#3 - Keyboard focus generally works well in Browsers, but it's possible that the use of AWT in your context is causing some confusion.  Again, please log a report with a snippet that shows the problem.

#4 and #5 - See http://www.eclipse.org/swt/faq.php#browserapplets to start.  The WebKit-based Browser on OS X disables applets because the Java plug-in's attempt to launch a JVM to run the applet collides with the JVM that's already running SWT/Eclipse, and crashes.  You'll notice in the FAQ that there are some specific contexts where a Browser will display applets, but what differentiates these contexts is that they always launch the JVM for running the applet out-of-process, which avoids the JVM collision that occurs otherwise.

Regarding Browser.getWebBrowser() returning something from WebKit, this is not something we would do because we don't expose objects without well-defined API.  WebBrowser subclasses utilized by Browser are internal implementation, and do not expose public methods that are not already accessible indirectly via Browser API.

Grant



"Dermot Doherty" <dermot@xxxxxxxxxxx>
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10/02/2011 09:21 PM

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Re: [platform-swt-dev] SWT browser







Thanks Scott. Yes, lots of good info here.

#4 - SWT WebKit disabling Java - It would be good to look into removing that
for the Mac Cocoa WebKit implementation and also the Windows WebKit
implementation. I tested a simple applet on Windows WebKit and Mac WebKit
and yes, without the Java being enabled, applets do not work. I suspect that
applets should work, given that applets work in Mac Safari which uses the
same Cocoa based WebKit. Applets also work in Windows Safari, so technically
applets should work in the Windows SWT WebKit browser also.

I am not sure if this is possible, but would it be possible to return a
handle on the WebKit object when calling Browser.getWebBrowser() from a
WebKit style Browser widget, just as calling Browser.getWebBrowser() returns
a handle on the JavaXPCOM nsIWebBrowser object when using Mozilla.

Browser.getWebBrowser() returns Object, so that object could be the
nsiWebBrowser object or the WebKit object depending on the browser style.

Something like this for Mozilla:

      nsIWebBrowser webBrowser = (nsIWebBrowser)browser.getWebBrowser();

and this for WebKit:

      WebKit webBrowser = (WebKit)browser.getWebBrowser();

It would be nice to get a handle on that WebKit object to take advantage of
more in-depth browser features (like enabling/disabling Java as per a users
preference).

Dermot

----- Original Message -----
From: "Scott Kovatch" <skovatch.swt@xxxxxxxxx>
To: "Eclipse Platform SWT component developers list."
<platform-swt-dev@xxxxxxxxxxx>
Sent: Thursday, February 10, 2011 6:13 PM
Subject: Re: [platform-swt-dev] SWT browser


>I can answer a few of these, but Grant will likely need to answer some of
>them.
>
> On Feb 10, 2011, at 3:05 PM, Dermot Doherty wrote:
>
>> 2) Both Mozilla and WebKit on Mac throw a "java.lang.NoSuchMethodError:
>> doubleValue". It is difficult to pinpoint exactly where this is
>> occurring, but it seems to happen when I create a new SWT browser
>> instance.
>> This is not happening on Windows.
>> See the log output below:
>> java.lang.NoSuchMethodError: doubleValue
>> at org.eclipse.swt.internal.cocoa.OS.objc_msgSendSuper(Native Method)
>> at org.eclipse.swt.widgets.Display.applicationSendEvent(Unknown Source)
>> at org.eclipse.swt.widgets.Display.applicationProc(Unknown Source)
>
> Given that it's java.lang.NoSuchMethodError that makes me think we're
> using reflection somewhere but the object we invoke it on doesn't have
> that method. But, I don't see any uses that call doubleValue. It's
> especially odd to see it during objc_msgSendSuper. Check Console.app to
> see if you're getting any additional information.
>
> If you have a simple test case that can reproduce it, please file a bug.
>
>>  4) SWT WebKit browser on Mac disables Java when embedded in Safari.
>> Explanation: When a SWT WebKit Browser is embedded in a Java applet on
>> Mac the "Enable Java" preference gets disabled. This is not happening
>> when the Mozilla engine is used.
>> Is there something in the WebKit implementation that automatically
>> disables Java that may be getting picked up by Safari which is also using
>> the same WebKit engine. This only happens for the first SWT WebKit
>> browser that is embedded. Subsequently embedded SWT WebKit browsers on
>> the same page do not disable the Java (after manually enabling the Java
>> in Preferences > Security).
>
> See WebKit.java:
>
> WebPreferences.standardPreferences().setJavaEnabled(false);
>
> But, it's only called once during initialization. I suspect
> standardPreferences() are per-user, so it makes sense that turning it on
> again in Java Preferences would enable it again for any additional Browser
> widgets created.
>
> This is probably a holdover from Carbon. I seem to recall a situation
> where you could end up embedding Cocoa (WebKit) into Carbon and then
> somehow putting a Carbon view into the Browser. And you can't mix Carbon
> and Cocoa that way, so it makes sense to block applets. In Cocoa there may
> not be a reason to prevent that.
>
>> 5) Do Java Applets run in the SWT WebKit browser?
>
> I don't know that we've ever tried. On the Mac it may work now in Cocoa,
> but you'd have to rebuild the SWT to try it out.
>
> Hope some of that helps.
>
> -- Scott K.
>
> ------------------
> Scott Kovatch
> IBM
> Eclipse Platform Team
> Pleasanton, CA
>
>
>
> _______________________________________________
> platform-swt-dev mailing list
> platform-swt-dev@xxxxxxxxxxx
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