Java Streams - Get a “symmetric difference list” from two other lists

Question

Im trying to use Java 8 streams to combine lists. How can I get a \"symmetric difference list\" (all object that only exist in one list) from two existing lists. I know how

Answer 1

An alternative approach, albeit not as elegant as one line streams:

    HashMap y = new HashMap<>();
    bigCarSet ().forEach(i -> y.put(i, !y.containsKey(i)));
    bigCarList().forEach(i -> y.put(i, !y.containsKey(i)));
    y.entrySet().stream().filter(Map.Entry::getValue).map(Map.Entry::getKey)
     .collect(Collectors.toList());

which can be simplified to at least:

    HashMap y = new HashMap<>();
    Stream.concat(list1.stream(), list2.stream()).forEach(i -> y.put(i, !y.containsKey(i)));
    y.entrySet().stream().filter(Map.Entry::getValue)
                 .map(Map.Entry::getKey).collect(Collectors.toList());