A 'data type' is a definition that explains how to build a specific data structure. When information is being transmitted between the Anno-J client and data providers (fetchers), the exchange is expected to take place making use of defined data types.
All data structures in Anno-J are transmitted using JSON strings. JSON has been chosen to replace XML due to ease of use.
To prevent clobbering, each data type should have a namespace to resolve naming clashes. By default, all data types within Anno-J fall under the namespace 'Annoj.DataTypes', unless otherwise specified. You may often see this abbreviated to 'AD'.