A specification for hierarchical repositories.
JCR implementation used by Fedora 4.
Aa authentication provider.
A source code metrics tool.
A continuous-integration tool.
A light-weight server container.
The framework used by Modeshape for a data grid.
The default key-value store used by Fedora 4.
Clustering technology.
A dependency-injection framework (a container that wants to manage everything, in practice).