What difference between Jersey vs jax-rs

JAX-RS is an specification (just a definition) and Jersey is a JAX-RS implementation.

Straight from the jersey site

Jersey framework is more than the JAX-RS Reference Implementation. Jersey provides its own API that extend the JAX-RS toolkit with additional features and utilities to further simplify RESTful service and client development. Jersey also exposes numerous extension SPIs so that developers may extend Jersey to best suit their needs.

JAX-RS is an specification and Jersey is a JAX-RS implementation.- True

This can be understood relating it to OOPS principles JAX-RS is an Interface and Jersey is a class implementing that interface.

These Specification creates a STANDARD for developing and using the web services.

There are other JAX-RS implementations too like wink, RestEasy.

JAX-RS is a specification which specifies how can we implement the web services,that what would be input type, input format, output type, its format, its configuration etc.Its Just a type declaration and its implementation are these libraries, Jersey, wink RestEasy etc.

Further, Java also have specification like JPA(Java Persistence API) and like mentioned above there is Hibernate which is an implementation of JPA.

JAX-RS is an specification (just a definition) and Jersey is a JAX-RS implementation. Jersey framework is more than the JAX-RS Reference Implementation. Jersey provides its own API that extend the JAX-RS toolkit with additional features and utilities to further simplify RESTful service and client development.