Writing Java Class Based Web Services

Writing Java class based Web Services involves building a Java class that includes one or more methods. When a Web Services client makes a service request, Oracle Application Server Web Services invokes a Web Services Servlet that runs the method that implements the service request. There are very few restrictions on what actions Web Services can perform. At a minimum, Web Services generate some data that is sent to a client or perform an action as specified by a Web Service request.

This section shows how to write a stateful and a stateless Java Web Service that returns a string, "Hello World". The stateful service also returns an integer running count of the number of method calls to the service. This Java Web Service receives a client request and generates a response that is returned to the Web Service client.

The sample code is supplied on the Oracle Technology Network Web site,

http://otn.oracle.com/tech/java/oc4j/demos/1012/index.html

After expanding the Web Services demo.zip file, the Java class based Web Service is in the directory under webservices/demo/basic/java_services on UNIX or in\webservices\demo\basic\java_services on Windows.

Writing Stateless and Stateful Java Web Services

Oracle Application Server Web Services supports stateful and stateless implementations for Java classes running as Web Services, as follows:

• For a stateful Java implementation, Oracle Application Server Web Services uses a single Java instance to serve the Web Service requests from an individual client.
• For a stateless Java implementation, Oracle Application Server Web Services creates multiple instances of the Java class in a pool, any one of which may be used to service a request. After servicing the request, the object is returned to the pool for use by a subsequent request.