private Collection<PetType> makePetTypes() {
        Collection<PetType> petTypes = new ArrayList<>();
        petTypes.add(new PetType(){
            {
                setName("Dog");
            }
        });
        petTypes.add(new PetType(){
            {
                setName("Bird");
            }
        });
        return petTypes;
    }
Helper method to produce some sample pet types just for test purpose

@return {@link Collection} of {@link PetType}
src/test/java/org/springframework/samples/petclinic/web/PetTypeFormatterTests.java