Currently, the generated REST resources contain a @POST method for creating new entities and a @PUT method for updating an existing entity.

This set of semantics is appropriate for auto-generated Ids where the Ids would be created by the server, and cannot be specified by the client.

However, for JPA entities that do not contain a @GeneratedValue annotation, these semantics may not be unsuitable. It would be preferable to use only a @PUT method that is used to create and update the entities. This is primarily because the client gets to decide the resource/entity identifier, and hence, also the location of the resource.