We currently use Glassfish 3 and I really want to use Java 8. I tried upgrading to Glassfish 4, but I experienced two bugs in the Glassfish 4 code so I had to revert back to Glassfish 3. Will Glassfish 3 work with Java 8 or will I have to upgrade my application container?
No, it won't be possible (at the moment, maybe a workaround will occur later).
I tried Glassfish 3.1.1 and Glassfish 3.1.2.2 with the final Java 8 JDK which was released today. It doesn't even start the server, some OSGI exceptions are thrown.
As the comment to your question showed, it doesn't even work with earlier builds of Glassfish 4.0.
Update 2015:
It looks like there is a way to make it work with Glassfish 3.1.2.2.
Open the file /glassfish/domains/domain1/config/osgi.properties of your Glassfish installation and add the following line at the end of the file: jre-1.8=${jre-1.7}
This should make the server start with JDK 8. It still doesn't work for Glassfish 3.1 or 3.1.1.
See also: