PicoContainer3 in Git at Github and Codehaus (mirrors) is a work in progress.  
The major piece that's taking a while to do is JSR330 compatibility.

   Run tests - PicoContainerJsr330Tests - to see how far we have to go.

PicoContainer 3.x is good enough to use in production, but it is not finished yet.

If you want stability choose PicoContainer2 which is still at Codehaus in Subversion.

   Source here: https://svn.codehaus.org/picocontainer/java/2.x/trunk
   Binaries here: https://nexus.codehaus.org/content/repositories/releases/org/picocontainer/picocontainer/2.12/

The Website for PicoContainer itself is http://picocontainer.org 
Presently, it is for the 2.x series of releases.