The feature packaging information is placed into a separate Java .jar. Standard Java jar facilities are used for constructing feature archives. Feature archives reference separately packaged plug-in archives (see next section) and non-plug-in files.
Features are identified using a structured identifier based on the provider internet domain name. For example, organization eclipse.org produces feature org.eclipse.jdt. The character set used for feature identifiers is as specified for plug-in identifiers (see Plug-in Manifest).
The recommended convention for naming the feature archives is
<id>_<version>.jar
Where <id> is the feature identifier and <version> is the full version identifier contained in the respective feature.xml. Note that this is a recommended convention that minimizes chance of collisions, but is not required by the Eclipse architecture. For example, the following are valid feature archive names
org.eclipse.jdt_2.0.0.jar
org.eclipse.pde_2.0.jar
my_feature.jar
Internally, each feature archive is packaged relative to its feature directory (but not including the directory path element). The archive has the following structure
feature.xml
feature<_locale>.properties (see "Translated Feature Information")
other feature files and subdirectories (TBD)
META-INF/
Java jar manifest and security files