// Animal.pj
public class Animal
 personifies Tracer
{
  private String     name;
  private Integer    code;
  void    setName(String n) { name = n; }
  String  getName() { return name; }
  void    setCode(Integer i) { code = i; }
  Integer getCode() { return code; }
  // --- for Tracer
  //  (nothing in its DI)
}