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.

File upload webapp

I recently became frustrated with the lack of easily self-hosted file upload app options. I needed to replace my employer's reliance on giant email attachments with something that wouldn't melt our mail server - and our clients could still understand how to use. This unfortunately ruled out the classic options like anonymous FTP.

In the end I wrote a new web application to accept files from clients over http and save them to a shared folder on the internal network. Many of the building blocks like uploadify were available, but there wasn't much around in terms of complete applications to do the job. Instead, people seemed to be using services like YouSendIt, Box.net, DropSend, etc ... which have downsides including:

• Inability to provide a canned recipient list, or high per-user per-month fees to support one
• Inability to customise the site's appearance and integrate it into your domain - without paying high fees for an "enterprise" version
• The need to download files once the client has sent them to the provider, often one-by-one via a clumsy web interface
• Windows-only client applications required to do batch downloads of files. Some services have Mac versions, but only one had a Linux client suitable for our advertising thin clients.
• Lack of a web services API - unless you pay high fees for the "enterprise" version.
• Lack of no-flash fallback upload methods
• Sometimes iffy browser compatibility

I wanted something really simple for clients - and staff - to use, that simply dropped files into a shared folder as they were uploaded and sent a notification email to staff when the upload was finished. Now that I've finished it, I'm releasing the result as open source software for the use of anybody who wants it. You can get it here:

https://github.com/ringerc/postupload

It's a Java EE 6 project that runs on Glassfish. Don't stress if you've never used any of that before, if you only know PHP, etc. The client-side is all familiar HTML and JavaScript, and the server side isn't especially complicated code. Detailed instructions for installing and running Glassfish are provided.