Deserializing Map<Class<? extends Object>, String>

[Ludevik]

I am having problems deserializing my Map<Class<? extends Object>, String>. Simple test case demonstrates it:

@Test
public void testMapWithClassAsKey() throws Exception {
    Map<Class<? extends Object>, String> map = new HashMap<>();
    map.put(ArrayList.class, "ArrayList");
    map.put(HashMap.class, "HashMap");

    ObjectMapper mapper = new ObjectMapper();

    String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(map);
    System.out.println(json);
    mapper.readValue(json, new TypeReference<Map<Class<? extends Object>, String>>(){});
}

This test serializes the map as:

{
    "class java.util.ArrayList" : "ArrayList",
    "class java.util.HashMap" : "HashMap"
}

mapper.readValue(json, new TypeReference<Map<Class<? extends Object>, String>>(){}); then throws a Exception:

com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not construct     Map key of type java.lang.Class from String "class java.util.ArrayList": not a valid representation: Can not construct Map key of type java.lang.Class from String "class java.util.ArrayList": unable to parse key as Class
 at [Source: ...

As i understood from #630 the KeyDeserializer for Class should be part of Jackson. Am I missing something?

[cowtowncoder]

Looks like problem is with serialization, not deserialization -- output is not correct, as it appears to use Class.toString(). So need to have a look at MapSerializers handling of key types.

[cowtowncoder]

Added handling of Class<?> keys; unfortunately key serializers are separate from value serializers.