@Oneway indicates that the given web method has only an input message and no output. Typically, a oneway method returns the thread of control to the calling application prior to executing the actual business method.

@WebService (name="PingEndpoint")
@SOAPBinding(style = SOAPBinding.Style.RPC)
public class PingEndpointImpl
{
 private static String feedback;
.. 
@WebMethod
@Oneway
public void ping()
{
log.info("ping");
feedback = "ok";
}
.. 
@WebMethod
public String feedback()
{
log.info("feedback");
return feedback;
}
}