FilterCarByBrandApproach1.java

// business logic
public static List<Car> filterCarsByBrand(List<Car> cars, String brand) {
  ArrayList<Car> filteredCars = new ArrayList<Car>();
  for (Car car : cars) {
    if (brand.equals(car.getBrand())) {
      filteredCars.add(car);
    }
  }
  return filteredCars;
}

...

// from your programm, you can call it from this way
List<Car> filteredCars = filterCarsByBrand(cars, "Ferrari");