为什么总是forEach以随机顺序打印数字，而collect始终从原始顺序收集元素，即使是从并行流中呢？

Integer[] intArray = {1, 2, 3, 4, 5, 6, 7, 8};
List<Integer> listOfIntegers = new ArrayList<>(Arrays.asList(intArray));

System.out.println("Parallel Stream: ");
listOfIntegers
  .stream()
  .parallel()
  .forEach(e -> System.out.print(e + " "));
System.out.println();

// Collectors         
List<Integer> l = listOfIntegers
  .stream()
  .parallel()
  .collect(Collectors.toList());
System.out.println(l);

输出：

Parallel Stream: 
8 1 6 2 7 4 5 3 
[1, 2, 3, 4, 5, 6, 7, 8]