SOAP stands for Simple Order Access Protocol. Its a protocol specification where messages are sent in XML format over http protocol. For more information, please visit here.
JAX-WS is a set of API for creating SOAP web services. It is often used with JAXB for binding i.e. to transform XML to Java objects and vice versa. Few popular implementations are CXF (By Apache), Axis2 (By Apache) and Metro (By Oracle).
Create a simple SOAP web service document style using CXF APIs
Create a simple SOAP web service with parameter style as Wrapped using CXF
Create a simple SOAP web service document style using Axis2 APIs