The @javax.ws.rs.OPTIONS annotation designates a method to respond to the HTTP OPTIONS requests. This method is useful for obtaining a list of HTTP methods allowed for a resource.
The JAX-RS runtime will offer a default implementation for the OPTIONS method type if the REST resource is missing an explicit implementation. The default implementation offered by the runtime sets the Allow response header to all the HTTP method types supported by the resource.
The JAX-RS annotations that we discussed in this section are the commonly used APIs for building a typical RESTful web service application. If you want to try out a simple JAX-RS application at this moment, you can jump to the Building your first RESTful web service with JAX-RS section. Later, you can come back and finish reading the rest of the topics discussed in this chapter.