Consider the following code sample:

        Stream<Double> stream = new TreeMap<Double, Double>() {{
            put(41.0, 41.0);
            put(10.0, 10.0);
            put(33.0, 33.0);
            put(22.0, 22.0);
        }}.values().stream();

        Stream parallel = (Stream)stream.distinct().parallel();
        Iterator iterator = parallel.iterator();
        System.out.println("next = " + iterator.next());
        System.out.println("next = " + iterator.next());
        System.out.println("next = " + iterator.next());
        System.out.println("next = " + iterator.next());
        System.out.println("next = " + iterator.next());



The output is not perfectly expected as the ascending order is not present:

next = 22.0
next = 41.0
next = 33.0
next = 10.0
Exception in thread "main" java.util.NoSuchElementException
at java.util.Spliterators$1Adapter.next(Spliterators.java:688)


The following JCK tests will fail due to this:

api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapValueParallelStream[checkDistinct]
api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapValueStream[checkDistinct]
api/java_util/TreeMap/ValuesStream.html#ValuesStream[checkDistinct]
api/java_util/TreeMap/ValuesParallelStream.html#ValuesParallelStream[checkDistinct]
api/java_util/Collections/synchronizd/index.html#SynchronizedSortedMapValueStream[checkDistinct]
api/java_util/Collections/synchronizd/index.html#SynchronizedSortedMapValueParallelStream[checkDistinct]