The Discovery Component is about discovering, or finding, implementations for
pluggable interfaces. It provides facilities instantiating classes in general,
and for lifecycle management of singleton (factory) classes.

Fundamentally, Discovery locates classes that implement a given Java interface.
The discovery pattern, though not necessarily this package, is used in many
projects including JAXP (SaxParserFactory and others) and commons-logging
(LogFactory). By extracting this pattern, other projects can (re)use it and
take advantage of improvements to the pattern as Discovery evolves.

Discovery improves over previous implementations by establishing facilities for
working within managed environments. These allow configuration and property
overrides without appealing to the global System properties (which are scoped
across an entire JVM). 

WWW:	http://commons.apache.org/discovery/