RESTful Web Services should be used when we need integration over the web. JAX-RS is the Java API for creating RESTful web services. It makes it easier to write web applications that are loosely coupled and have architectural simplicity.

SOAP web Services are more applicable in Enterprise Application Integration scenarios which have advanced QoS requirements. JAX-WS is the latest Java API used for creating SOAP based web services. It makes it easier to support WS-* set of protocols which provide standards for security, reliability and interoperate with other WS-* conforming clients and servers.