This issue is caused by change made on Grizzly long time ago,
/HashMap attributes = new HashMap()/
changed to
/Map attributes = new ConcurrentHashMap();/
the problem is that ConcurrentHashMap unlike HashMap doesn't allow null
values.
Don't want to roll the change back, cause not sure what was the reason
for it and 3.1.1 release is very close at this point.
I can just provide a patch for GF 3.1, so you can use it.
Can I ask you to file an issue in the GlassFish issue tracker [1]?
Thanks.
WBR,
Alexey.
[1]
http://java.net/jira/browse/GLASSFISH