From OSGi Community Wiki
Apache Felix is an implementation of the OSGi Service Platform, released under an Apache License. Felix is also the name of the top-level project which is used for development of OSGi bundles and related build systems.
Felix can be launched using
java -jar felix.jar
which brings up a Shell that can be used to introspect the state of the system.
./posh -F Welcome to Paremus Nimble! Type 'help' for help. [local.0]% lsb | grep '0 ACTIVE' 0 ACTIVE org.apache.felix.framework:3.2.1