Synchronizing on the session object could be ineffectual due to the servlet implentation not providing reference stability

[VsevolodGolovanov]

Mojarra synchronizes on the session object in some places, but at least Undertow 2.0.15.Final returns a different instance (wrapper) from HttpServletRequest#getSession for every request in the same session.
A simple text search of "synchronized (ses" in mojarra-2.3.21-RELEASE sources yields:

\impl\src\main\java\com\sun\faces\application\view\ViewScopeContextManager.java
\impl\src\main\java\com\sun\faces\renderkit\ServerSideStateHelper.java
\test\servlet30-isolated\cactus\src\main\java\com\sun\faces\application\DeprStateManagerImpl.java

This is issue is a follow up to this.

[mnriem]

@VsevolodGolovanov Can you create a PR for the suggested changes?

[BalusC]

I prepped a PR for 4.0.

Feel free to backport for 2.3.

[pizzi80]

I don't know if someone can help...
AFAYK:

Does this also apply to Tomcat?

Can this create a race condition with ajax requests backed by ViewScoped beans?

I'm experiencing some very strange hanging threads
on POST (ajax) requests on Tomcat
with no visible UI error and no exceptions on the server log.