JAX-RS: Java API for RESTful Web Services (JAX-RS) is a Java programming language 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.
Jersey RESTful Web Services , formerly Glassfish Jersey, currently Eclipse Jersey framework is an open source framework for developing RESTful Web Services in Java. It provides support for JAX-RS APIs and serves as a JAX-RS (JSR 311 & JSR 339) Reference Implementation. But, it is also more than the Reference Implementation. Jersey provides an API so that developers may extend Jersey to suit their needs.