Set.of() (Java 9) cannot be deserialized with polymorphic handling

[Sam-Kruglov]

Hi, 2.13.0 doesn't seem to work with Set.of() and I don't see any tests for it, there're only for List.of() and Map.of().

Originally posted by @Sam-Kruglov in #2900 (comment)

public static void main(String[] args) throws Exception {
    ObjectMapper mapper = JsonMapper.builder()
            .findAndAddModules()
            .activateDefaultTyping(LaissezFaireSubTypeValidator.instance, EVERYTHING, JsonTypeInfo.As.PROPERTY)
            .build();
    Set<?> set = Set.of("a", "b", "c");
    String actualJson = mapper.writeValueAsString(set);
    Set<?> output = mapper.readValue(actualJson, Set.class);
}

Output:

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `java.util.ImmutableCollections$SetN` (no Creators, like default constructor, exist): no default no-arguments constructor found

Same example with List.of() works and is already here:

jackson-databind/src/test-jdk14/java/com/fasterxml/jackson/databind/failing/Java9ListsTest.java

Lines 50 to 53 in f584290

	list = List.of("a", "b", "c");
	actualJson = MAPPER.writeValueAsString(list);
	output = MAPPER.readValue(actualJson, List.class);
	assertEquals(3, output.size());

[cowtowncoder]

Since tests are under failing, likely those won't work on later JDKs either. But definitely worth adding a test for Set as well.

[Sam-Kruglov]

I can confirm that I was running this example on JDK 11 on 2.13.0 and List.of() works fine