JAX-RS stands for Java API extension for RESTful Web services. JAX-RS is a specification that defines a set of APIs for developing web services in REST architecture style. This has become very popular in the past few years and is commonly used to build microservices. As previously discussed, RESTful services are interoperable services that interact with each other over the network, and JAX-RS helps us to build these services.

JAX-RS is Java's implementation for the REST style of architecture. This is a collection of Java annotations and interfaces that aid in developing RESTful web services. Here, there are both client- and server-side APIs, which are designed to do REST-based development in Java EE. JAX-RS specification was standardized in Java EE 6, the JAX-RS version was updated to JAX-RS 2.0 in Java EE 7, and this was improved in Java EE 8.

JAX-RS provides support for developing and consuming RESTful web services. JAX-RS is a set of Plain Old Java Object (POJO) based resource classes with some standard annotations on it, and this is designed to use a stateless communication model, such as HTTP. It specifies how to create an endpoint using POJOs as resources using the HTTP protocol, and uses either XML or JSON to represent the data.