[Java Stream] double[] 을 List<Double>로 / List<Double>을 double[]로 바꾸기

import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.DoubleStream;

... 중략 ...

// double[] 을 List<Double> 로 변환하기
List<Double> doubleList = DoubleStream.of(outReal)
                            .boxed()
                            .collect(Collectors.toList());


// List<Double> 을 double[] 배열로 변환하기
double[] arrDouble = doubleList.stream()
                        .mapToDouble(Double::doubleValue)
                        .toArray();