The class must extend AbstractEntityBOBuilder. The primary key data type and the entity's Dtls data type are Long and UserToDoLinkDtls respectively. Hence, these types must be specified in the class declaration as follows:
class UserToDoLinkEntityBOBuilder extends AbstractEntityBOBuilder<Long, UserToDoLinkDtls>{ }
The method getName() has to be overridden in order to return the name of the entity that is unique across the system - i.e. in this case, the string UserToDoLink can be returned.
The method getEntityAdapter() has to be overridden to return an instance of the adapter class, i.e. UserToDoLinkAdapter.