Consider the following code:

         Stream<String> stream = new TreeMap<String, String>() {{
            put("c", "c");
            put("d", "d");
            put("b", "b");
            put("a", "a");
        }}.values().stream();

        Stream parallel = (Stream)stream.substream(1).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());


The output will be

next = a
next = b
next = c
Exception in thread "main" java.util.NoSuchElementException
at java.util.Spliterators$1Adapter.next(Spliterators.java:688)

Which is not expected according to the specification of method Stream.substream():

     * Returns a stream consisting of the remaining elements of this stream
     * after indexing {@code startInclusive} elements into the stream.


The following JCK tests will fail due to this issue:

api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapValueStream[checkSubstream]
api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapValueStream[checkSubstream2]api/java_util/TreeMap/ValuesStream.html#ValuesStream[checkSubstream]
api/java_util/TreeMap/ValuesStream.html#ValuesStream[checkSubstream2]
api/java_util/TreeMap/ValuesParallelStream.html#ValuesParallelStream[checkSubstream]
api/java_util/TreeMap/ValuesParallelStream.html#ValuesParallelStream[checkSubstream2]