Jakarta RESTful Web Services

Jakarta RESTful Web Services (JAX-RS)
Original author(s)	Sun Microsystems
Developer(s)	Eclipse Foundation
Stable release	3.1.9 / October 17, 2024; 6 months ago
Repository	github.com/jakartaee/rest ;
Written in	Java
Operating system	Cross-platform
Platform	Java
Type	Application framework
License	EPL 2.0 or GPL v2 w/Classpath exception
Website	projects.eclipse.org/projects/ee4j.jaxrs

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.^[1] 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^[2]). 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.^[3]

On 2017-08-22 JAX-RS 2.1^[4] specification final release was published. Main new supported features include server-sent events, reactive clients, and JSON-B.^[5]