NullPointerException on @Inject site even with beans.xml?

Are you staring at a stack trace from a NullPointerException thrown by access to a CDI-injected site?

Have you checked to make sure beans.xml is in the right place:

• .jar and .rar: /META-INF/beans.xml
• .war: /WEB-INF/beans.xml
• .ear: an EAR can't be a bean archive

Still not working? Does a message about activating CDI appear in the server log, but injection still not work?

Make sure you used the right @Inject annotation. Especially with code completion and dependencies pulling Google's Guice onto the classpath it's easy to land up accidentally choosing com.google.inject.Inject instead of javax.inject.Inject.

Yep, I just wasted twenty minutes staring at code that wasn't working before I noticed this. Time to find out which dependency is pulling in Guice, add an exclusion, and nag them to make it an <optional>true</optional> dependency. It looks like in my case it's coming from org.jboss.shrinkwrap.resolver:shrinkwrap-resolver-impl-maven, so a quick:

<exclusion>
<groupId>org.sonatype.sisu</groupId>
<artifactId>sisu-inject-plexus</artifactId>
</exclusion>

ensured that mistake wouldn't happen again.

JBAS011440: Can't find a persistence unit named null in deployment

Encountering the deployment error "JBAS011440: Can't find a persistence unit named null in deployment" on JBoss AS 7? Using Arquillian?

You probably put your persistence.xml in the wrong place in your archive. Try printing the archive contents.

Arquillian initially overpromises and frustrates, but delivers real benefits

Arquillian is changing fairly rapidly, and the Arquillian folks are paying a lot of attention to feedback. This post discusses Arquillian 1.0.0.Final, and more importantly the ShinkWrap Resolver and ShrinkWrap Dependency extensions. A lot has already improved since I wrote this, though most of it hasn't hit -Final versions yet.

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After seeing a lot of talk, hype and excitement about Arquillian on twitter for several months, I finally got around to introducing it into a new project to give it a try. I'm told it'll make testing massively easier and save me tons of time, so using it is a no-brainer.

Tweet to @craigdevel After my recent experience I recommend that you start using it too - but you'll need to be prepared for some rough edges and the need for workarounds until a few point releases have gone by.

To jump straight to the summary of it all, click here, or read on for the whole experience.