Thank you for the informative replies.

My understanding with plugin2 and Swing back in Java 6 was that as long as 
the jvm parameters for each applet were the same, 2 applets on the same 
html page could share the jvm.

I can see, however, that JavaFX running in the native GUI thread would 
make it really hard to support 2 applets (and therefore 2 
javafx.application.Applications) in the same JVM.

To Kevin's question, we were looking for 2 things from multiple applets in 
a shared JVM:
1) reduced resource consumption compared to separate JVMs
2) hopefully easier inter applet communication

With a trivial Java 8 update 20 applet needing 141 Meg, if there are 
several, they can start to add up memory wise.

As to #2, we can probably have the multiple applets communicate through 
javascript (since the javascript support seems to be pretty strong). Not 
as elegant, but it will probably work.



From:   Kevin Rushforth <>
To:     Richard Bair <>, 
Cc:     Stephen F Northover <>,,
Date:   07/08/2014 03:48 PM
Subject:        Re: 2 JavaFX applets in the same JVM

Hi Neil,

What problem are you trying to solve? Running multiple applets in the same 
VM is a means to some end for you, so knowing what you are trying to do 
might lead to a discussion of another way to accomplish what you need.

-- Kevin

Richard Bair wrote: 
And to top it all off, supporting shared JVMs is extremely security 

On Jul 8, 2014, at 12:40 PM, Stephen F Northover 
<> wrote:

This would imply that there was more than on distinguished GUI thread per 
process.  JavaFX runs in the native GUI thread by design and more than one 
GUI thread is not supported in JavaFX and on some platforms (ie. Mac).


On 2014-07-08, 3:31 PM, Kevin Rushforth wrote:
Is running 2 JavaFX applets in the same JVM supported?
No, this is not supported. RT-29969 (and the non-public RT-32321) is about 
running multiple applets from the same web page, each in their own JVM. By 
design, JavaFX runs each applet in its own VM. It is very unlikely that we 
would ever add the ability to run more than JavaFX applet in the same VM.

-- Kevin wrote:

What is the status of running 2 JavaFX applets in the same JVM 
(separate_jvm = false)?
When we try to load 2 applets into the same JVM we get a runtime error (I 
think it was class loader related).

When I searched in jira I found RT-29969 (the 2 applet test it refers to 
may or may not be in the same JVM) which points to RT-32321 which seems to 
be private (it gives me an error when I try to access it).

Is running 2 JavaFX applets in the same JVM supported?

If not, is that a bug or a feature?



NOTICE from Ab Initio: This email (including any attachments) may contain 
information that is subject to confidentiality obligations or is legally 
privileged, and sender does not waive confidentiality or privilege. If 
received in error, please notify the sender, delete this email, and make 
no further use, disclosure, or distribution. 

Reply via email to