Getting Primeface and JSF EL to work on Google App Engine

Lately I decided to use the Google cloud infrastructure as runtime foundation for a new project. At least two reasons led to a positive decision towards Google's App Engine: (1) a very strict but straight development paradigm and (2) the availability of a free quota.

Since I need to get some presentable results quickly and did not want to spend precious time learning a new ui framework, I chose to try out the availability of JSF 2.0 on GAE in interaction with Primefaces. Fortunately I stumbled across an article by Derek Berube on how to setup Primefaces in a GAE environment.

Unfortunately I ran into two small but annoying errors that kept me away from making any progress for a while. The first one appeared everytime I requested a JSF page:

java.lang.UnsupportedOperationException
at javax.faces.context.FacesContext.getCurrentPhaseId(FacesContext.java:660)
at javax.faces.event.ExceptionQueuedEventContext.(ExceptionQueuedEventContext.java:158)
at javax.faces.event.ExceptionQueuedEventContext.(ExceptionQueuedEventContext.java:106)

I could get rid of it by replacing the recommended Mojarra version 2.0.4 by 2.0.3.

The second problem is associated with SUNs implementation of the expression language. So, I replaced it by the JBoss implementation but had to make changes to get it working, since it breaks the law of not spawning any threads. Therefore I copied the modified contents of org.jboss.el.util.ReferenceCache
into the source folder of my project.

Finally I got my project using Primefaces 2.2.1 and JBoss-EL 2.0.1 working.