The top-down development strategy begins with the abstract contract for the service, which includes the WSDL file and zero or more schema files. The wsconsume tool is then used to consume this contract, and produce annotated Java classes (and optionally sources) that define it.

Using the WSDL file from the bottom-up example, a new Java implementation that adheres to this service can be generated. The "-k" option is passed to wsconsume to preserve the Java source files that are generated, instead of providing just classes:

 
  
$ wsconsume -k EchoService.wsdl
echo/Echo.java
echo/EchoResponse.java
echo/EchoService.java
echo/Echo_Type.java
echo/ObjectFactory.java
echo/package-info.java
echo/Echo.java
echo/EchoResponse.java
echo/EchoService.java
echo/Echo_Type.java
echo/ObjectFactory.java
echo/package-info.java
 

The following table shows the purpose of each generated file:

Examining the Service Endpoint Interface reveals annotations that are more explicit than in the class written by hand in the bottom-up example, however, these evaluate to the same contract:

@WebService(name = "Echo", targetNamespace = "http://echo/")
public interface Echo {
@WebMethod
@WebResult(targetNamespace = "")
@RequestWrapper(localName = "echo", targetNamespace = "http://echo/", className = "echo.Echo_Type")
@ResponseWrapper(localName = "echoResponse", targetNamespace = "http://echo/", className = "echo.EchoResponse")
public String echo(
@WebParam(name = "arg0", targetNamespace = "")
String arg0);
  
}

The only missing piece (besides the packaging) is the implementation class, which can now be written, using the above interface.

package echo;
  
@javax.jws.WebService(endpointInterface="echo.Echo")
public class EchoImpl implements Echo
{
public String echo(String arg0)
{
return arg0;
}
}