Description of problem:

I've been doing development of plugins and noticed the following in the logs.

2012-02-05 20:47:36,072 INFO  [org.rhq.enterprise.server.discovery.DiscoveryServerServiceImpl] Error processing availability report from [vg61l01ad-hadoop002]: javax.ejb.EJBException:java.lang.NullPointerException -> java.lang.NullPointerException:null

I traced the problem down to something being null in AvailabilityManagerBean.mergeAvailabilityReport().

It's not clear if the issue is coming from a bad plugin. My plugin would fail to return from its start() method and I suppose this might have prevented some database process from occurring.

The resources do appear in the tree, however, they are all unavailable.


Version-Release number of selected component (if applicable):

RHQ 4.1, but the code seems to not have changed recently.


How reproducible:

Removing the resource (server) and discovering it again doesn't seem to cause it to clear.


Steps to Reproduce:
1. Create a bad(?) plugin; deploy
2. Discovery fails (or never completes) as the start() method fails.
3. Notice the logs
  
Expected results:

The server should guard against bad data and provide some indication what was bad about the data.


Additional info:

I will provide more information as I find it.