Jakarta RESTful Web Services, (JAX-RS; formerly Java API for RESTful Web Services) is a Jakarta EE API specification that provides support in creating web services according to the Representational State Transfer (REST) architectural pattern. JAX-RS uses annotations, introduced in Java SE 5, to simplify the development and deployment of web service clients and endpoints.

From version 1.1 on, JAX-RS is an official part of Java EE 6. A notable feature of being an official part of Java EE is that no configuration is necessary to start using JAX-RS. For non-Java EE 6 environments a small entry in the web.xml deployment descriptor is required.

Specification

JAX-RS provides some annotations to aid in mapping a resource class (a POJO) as a web resource. The annotations use the Java package jakarta.ws.rs (previously was javax.ws.rs but was renamed on May 19, 2019). They include:

  • @Path specifies the relative path for a resource class or method.
  • @GET, @POST, @PUT, @PATCH (since JAX-RS 2.1), @DELETE, @HEAD and @OPTIONS (since JAX-RS 1.1) specify the HTTP request type of a resource.
  • @Produces specifies the response Internet media types (used for content negotiation).
  • @Consumes specifies the accepted request Internet media types.

In addition, it provides further annotations to method parameters to pull information out of the request. All the @*Param annotations take a key of some form which is used to look up the value required.

  • @PathParam binds the method parameter to a path segment.
  • @QueryParam binds the method parameter to the value of an HTTP query parameter.
  • @MatrixParam binds the method parameter to the value of an HTTP matrix parameter.
  • @HeaderParam binds the method parameter to an HTTP header value.
  • @CookieParam binds the method parameter to a cookie value.
  • @FormParam binds the method parameter to a form value.
  • @DefaultValue specifies a default value for the above bindings when the key is not found.
  • @Context returns the entire context of the object (for example @Context HttpServletRequest request).

JAX-RS 2.0

In January 2011 the JCP formed the JSR 339 expert group to work on JAX-RS 2.0. The main targets are (among others) a common client API and support for Hypermedia following the HATEOAS-principle of REST. In May 2013, it reached the Final Release stage.

On 2017-08-22 JAX-RS 2.1 specification final release was published. Main new supported features include server-sent events, reactive clients, and JSON-B.

Implementations

Implementations of JAX-RS include:

External links

Tutorials