test/java/util/stream/test/org/openjdk/tests/java/util/stream/CollectorsTest.java

@@ -515,11 +515,11 @@
                               new GroupingByAssertion<>(classifier, HashMap.class,
                                                         new MappingAssertion<>(mapper,
                                                                                new ToListAssertion<>())));
     }
 
-    @Test
+    @Test(groups = { "serialization-hostile" })
     public void testFlatMappingClose() {
         Function<Integer, Integer> classifier = i -> i;
         AtomicInteger ai = new AtomicInteger();
         Function<Integer, Stream<Integer>> flatMapper = i -> Stream.of(i, i).onClose(ai::getAndIncrement);
         Map<Integer, List<Integer>> m = Stream.of(1, 2).collect(groupingBy(classifier, flatMapping(flatMapper, toList())));