This is necessary only if you would like to run the sample under Eclipse.
Please refer to the Virgo Programmer Guide for installation instructions of the Virgo tooling. See Documentation.
This sample also uses Maven and to support the build in Eclipse you need to install the m2e plugin.
This is simple to do from the 'Help' -> 'Install New Software..' menu item. Add a new update site of
http://download.eclipse.org/technology/m2e/releases/ and then use it to install the plugin.