Annotations play a critical role in JAX-WS web services.
Annotations are used in mapping Java to WSDL and
schema files. They are used at runtime to control how the
JAX-WS runtime processes and responds to web service invocations.
At the time of writing, the annotations utilized by JAX-WS are defined in
separate JSRs:
JSR 181: Web Services Metadata for the Java Platform
JSR 222: Java Architecture for XML Binding (JAXB) 2.0
JSR 224: Java API for XML Web Services (JAX-WS) 2.0
JSR 250: Common Annotations for the Java Platform
For details, see
Web Service Annotations in the IDE
In the IDE, you can use code completion when working with annotations.