Deserialization with generic types not working since 2.7.0

[a-k-g]

package jackson.fail;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.core.Is.is;

import java.io.IOException;

import org.junit.Test;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;

public class GenericWrapperTest {

    @JsonSerialize(as = GenericWrapperImpl.class)
    @JsonDeserialize(as = GenericWrapperImpl.class)
    public interface GenericWrapper<T> {
        T getValue();
    }

    public static class GenericWrapperImpl<T> implements GenericWrapper<T> {
        private final T value;

        @JsonCreator
        public GenericWrapperImpl(@JsonProperty("value") T value) {
            this.value = value;
        }

        @Override
        public T getValue() {
            return value;
        }
    }

    public static class Vehicle {
        private final String name;
        private final String make;

        @JsonCreator
        public Vehicle(@JsonProperty("name") String name, @JsonProperty("make") String make) {
            this.name = name;
            this.make = make;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }

            Vehicle vehicle = (Vehicle) o;

            if (!name.equals(vehicle.name)) {
                return false;
            }
            return make.equals(vehicle.make);

        }

        @Override
        public int hashCode() {
            int result = name.hashCode();
            result = 31 * result + make.hashCode();
            return result;
        }
    }

    @Test
    public void deserialization() throws IOException {
        Vehicle expected = new Vehicle("Civic", "Honda");
        String json = "{\"value\": { \"name\" : \"Civic\", \"make\" : \"Honda\"}}";
        ObjectMapper mapper = new ObjectMapper();
        final GenericWrapper<Vehicle> deserialized =
                mapper.readValue(json, new TypeReference<GenericWrapper<Vehicle>>() {});
        assertThat(deserialized.getValue(), is(expected));
    }
}

This test fails with 2.7.0+ and works with 2.6.6. The problem seems similar to #921, but isn't the same.

[a-k-g]

Mentioning the actual error seen in 2.7 for searchability of this issue - java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to

[cowtowncoder]

This could be something related to #1186, which was fixed for 2.7.4. So 2.7.4-SNAPSHOT may have a fix. The problem there was the way type specialization works; in this case that'd be for @JsonDeserialize(as=....).

Note, too, that @JsonSerialize(as=...) is unnecessary here and probably should not be used, unless I am missing something.

[a-k-g]

Yeah, looks like 2.7.4 might fix it. Thanks for the quick response! Anywhere I can check when 2.7.4 is scheduled to be released?

Yes, you're right @JsonSerialize(as=...) is unnecessary here.

[cowtowncoder]

@a-k-g we are following "when it's ready" model, not date-driven, so there's no hard deadline.
But my current hope is to release this over the next weekend. Main remaining issues are with Scala module; when those are complete it's time for 2.7.4.
So I would say by end of April 2016.