// 交集

        List<String> intersection = list1.stream().filter(item -> list2.contains(item)).collect(toList());

        System.out.println("---得到交集 intersection---");

        intersection.parallelStream().forEach(System.out :: println);

        // 差集 (list1 - list2)

        List<String> reduce1 = list1.stream().filter(item -> !list2.contains(item)).collect(toList());

        System.out.println("---得到差集 reduce1 (list1 - list2)---");

        reduce1.parallelStream().forEach(System.out :: println);

        // 差集 (list2 - list1)

        List<String> reduce2 = list2.stream().filter(item -> !list1.contains(item)).collect(toList());

        System.out.println("---得到差集 reduce2 (list2 - list1)---");

        reduce2.parallelStream().forEach(System.out :: println);

        // 并集

        List<String> listAll = list1.parallelStream().collect(toList());

        List<String> listAll2 = list2.parallelStream().collect(toList());

        listAll.addAll(listAll2);

        System.out.println("---得到并集 listAll---");

        listAll.parallelStream().forEach(System.out :: println);

        // 去重并集

        List<String> listAllDistinct = listAll.stream().distinct().collect(toList());

        System.out.println("---得到去重并集 listAllDistinct---");

        listAllDistinct.parallelStream().forEach(System.out :: println);

        System.out.println("---原来的List1---");

        list1.parallelStream().forEach(System.out :: println);

        System.out.println("---原来的List2---");

        list2.parallelStream().forEach(System.out :: println);