Method count

reflection/PetCounter3.java:20–26

(Pet pet)

          Collectors.toMap(Pair::key, Pair::value)));
    }
    public void count(Pet pet) {
      // Class.isInstance() eliminates instanceofs:
      entrySet().stream()
        .filter(pair -> pair.getKey().isInstance(pet))
        .forEach(pair ->
          put(pair.getKey(), pair.getValue() + 1));
    }
    @Override public String toString() {
      String result = entrySet().stream()
        .map(pair -> String.format("%s=%s",