Why does registerTypeAdapter for Object not work?

[onriv]

just tried to custom deserializer for object, and wrote the following code but it dosn't work:

JsonDeserializer<Object> objectJsonDeserializer = new JsonDeserializer<Object>() {

    @Override
    public Object deserialize(JsonElement json,
                              Type typeOfT,
                              JsonDeserializationContext context) throws JsonParseException {
        // can't reach this statement
        return null;
    }
};
gsonBuilder.registerTypeAdapter(Object.class, objectJsonDeserializer);

and all other deserializers for other types like map, list, and custom class work fine.

[onriv]

found the reason at

gson/gson/src/main/java/com/google/gson/Gson.java

Line 224 in 855f049

factories.add(ObjectTypeAdapter.FACTORY);

so it seems just impossible to override the builtin deserializer for object.

But I want to deserialize decimal as BigDecimal, interger as Long, array as ImmutableList, object as ImmutableMap when wirting something like

gsonBuilder.create().fromJson("string", Object.class);

[NightlyNexus]

duplicate of #1177.