Fragment bundles in OSGi

Fragments are bundles that are attached to a host bundle by the Framework.Attaching is done as part of resolving: the Framework appends the relevantdefinitions of the fragment bundles to the host’s definitions before the hostis resolved. Fragments are therefore treated as part of the host, including any permitted headers.

These fragemnt bundles will not have a seperate class loader. these will belaoded by the same bundle class loader.For a bundle to be a fragment it has to mention fragment host in its manifest file.

This property of fragments can just be used for a logical seperation of classes , examples could be resource bundles which can be packed in to a seperate bundle.

Since these fragment bundles use the same class loader as the host bundlle there is no provision of seperately refreshing the fragment bundle

Ref : http://osgi.mjahn.net/2008/03/13/half-bundle-half-jar-%E2%80%93-the-nature-of-fragment-a-blessing-or-a-curse/