Consider the following code:

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        final HashMap<String, String> hashMap = new HashMap<>();
        hashMap.put("a", "b");
        final Set<Map.Entry<String, String>> set = Collections.checkedMap(hashMap, String.class, String.class).entrySet();
// final Set<Map.Entry<String, String>> set = Collections.unmodifiableMap(hashMap).entrySet();

        Map.Entry<String, String> e1 = set.iterator().next();
        Map.Entry<String, String> e2 = set.stream().findFirst().get();

        System.err.println("same instances? " + (e1 == e2));

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The output will be:

same instances? false

The following JCK tests fail due to this issue:


api/java_util/Collections/checked/index.html#CheckedMapEntrySetStream
api/java_util/Collections/checked/index.html#CheckedMapEntrySetParallelStream
api/java_util/Collections/checked/index.html#CheckedSortedMapEntrySetParallelStream
api/java_util/Collections/checked/index.html#CheckedSortedMapEntrySetStream
api/java_util/Collections/unmodifiable/index.html#UnmodifiableMapEntrySetStream
api/java_util/Collections/unmodifiable/index.html#UnmodifiableMapEntrySetParallelStream
api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapEntrySetParallelStream
api/java_util/Collections/unmodifiable/index.html#UnmodifiableSortedMapEntrySetStream