After deciding the classes which implement the Evidence2Compare interface, it is necessary to add these classes to the Evidence2Compare map that provides a look up for the implementing class using the evidence type. This can be done in two ways: using Google Guice module or by a registrar. Though both approaches achieve the same goal, the Google Guice route is preferred over the registrar route. Typically the registrar route should be used when overriding the OOTB implementation. Both approaches are outlined below using the Sample Sporting Activity evidence type referred to in the previous section: