NullPointerException during Repository.login in EJB Startup

The Repository.login is working fine for the REST client, but within a @javax.ejb.Singleton bean, the login could not be performed. A NullPointerException is thrown during the initialization of RepositoryCache (L:135). I tried to initialize the repository within a @PostConstruct method.

I debugged the code a little bit: Triggered by the REST client (RepositoryManager of example) we have the following (working) scenario in class RepositoryCache (constructor):

• Line 119: Get root node (1.) of system workspace
• root node's child reference is null, so a new one is created and saved at line 128
• the root node's child reference (2.) is looked up again at line 130
• root node (1.) and root node (2.) are different object references
• the systemRef in line 131 is resolved to a valid ChildReference
• -> the repository session is created

Triggered by the @javax.ejb.Singleton bean (@PostConstruct) the scenario in RepositoryCache changes to:

• Line 119: Get root node (1.) of system workspace
• root node's child reference is null, so a new one is created and saved at line 128
• the root node's child reference (2.) is looked up again at line 130
• root node (1.) and root node (2.) are THE SAME object references
• the systemRef in line 131 is resolved to null
• -> a NullPointerException occurs at line 135

Used in a non-startup bean, the repository can be obtained successfully as described for the REST client. There is a different behavior between Startup and "normal" execution. Might be a transaction problem, regarding to system.save() and re-lookup of root node?

See forum https://community.jboss.org/message/739667 for the problem thread.