If the authors are reading this: in your later articles, I'd love to see some details about what method of authentication and authorization you settled on for the REST API and how well it plays with Dropwizard.
The upshot is we settled on OAuth 2.0 with JWT auth tokens, along with some custom DropWizard filters and annotations to enforce authz. We found two-legged OAuth 2.0 pretty straightforward to implement and use.