return;

Personally I think that leaving a return statement at the end of a method whether you need one or not lets everyone know you really did mean to end the method there.

 /**
  * assign an interview to a person
  * 
  * @param personId
  * @param interviewName
  */
 @Oneway
 @WebMethod(operationName="assign")
 public void assign(
   @WebParam(name = "personId") String personId, 
   @WebParam(name = "interviewName") String interviewName
 ){
  InterviewEngine.assign(em, personId, interviewName);
  return;
 }

In other words, "Yes kids, I did mean to return there, no I didn't nod off and forget to finish the method."