Our example uses a single namespace:

namespace org.acme.loc

This namespaces says that the type definitions in this file have been defined by the Acme organization's letter of credit process. All this is a short name! Use namespaces–they'll help you clearly separate, and more importantly, communicate, your ideas. It is recommended to use a hierarchical name so that it's clear which organizations in the network are defining the relevant types being used by the network.