Raouf25

public interface CarRepository extends JpaRepository<Car, Long> {
 
	List<Car> findByManufacturer(String manufacturer, Pageable pageable);
 
	List<Car> findByModel(String model, Pageable pageable);
 
	List<Car> findByManufacturerAndModel(String manufacturer, String model, Pageable pageable);
 
	// other combinations omitted for sanity
} 

Raouf25

files.stream()
     .parallel()
     .map(wrapper(file->file.getInputStream()))
     .forEach(inputStream -> carService.saveCars(inputStream));

Raouf25

private <T, R, E extends Exception>
    Function<T, R> wrapper(FunctionWithException<T, R, E> fun) {
        return arg -> {
                        try {
                            return fun.apply(arg);
                        } catch (Exception e) {
                            throw new RuntimeException(e);
                        }
        };
}

Raouf25

@FunctionalInterface
interface FunctionWithException<T, R, E extends Exception> {
  R apply(T t) throws E;
}

Raouf25

  private InputStream extractInputStream(MultipartFile file) {
        try {
            return file.getInputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

Raouf25

files.stream()
      .parallel()
      .map(file-> extractInputStream(file))
      .forEach(inputStream -> carService.saveCars(inputStream));

Raouf25

files.stream()
   .parallel()
   .map(file-> {
       try {
           return file.getInputStream();
       } catch (IOException e) {
           e.printStackTrace();
           return null;
       }
   })

Raouf25

 for (final MultipartFile file : files) {
            try {
                carService.saveCars(file.getInputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

Raouf25

function	function signature	call
Getters	Function<City, String> fun = City::getName;	fun.apply();
Setters	BiConsumer<City, String> fun = City::setName;	fun.accept();
Default Constructor	Supplier< City> fun = City::new;	fun.get();
Parameter Constructors	BiFunction fun =City::new;	fun.apply();

Raouf25

// Use the City's constructor method reference to create
// a two-parameter constructor reference.
BiFunction<String, String, City> twoParameterConstructor = City::new;
City dc = twoParameterConstructor.apply("Washington, D.C.", "DC");