Testcase for https://github.com/FasterXML/jackson-databind/issues/658

gistfile1.java

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import java.io.File;
import java.io.IOException;
import java.util.Optional;

public class Main {

    @JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class)
    public static interface Task<Parent extends Task<?, ?>, Child extends Task<?, ?>> {

        Optional<Parent> getParent();

        Optional<Child> getChild();
    }

    @JsonPropertyOrder(
            {
                // Serializing "child" last improves readability
                "@id", "child"
            })
    public static abstract class AbstractTask<Parent extends Task<?, ?>, Child extends Task<?, ?>>
            implements Task<Parent, Child> {

        @JsonProperty
        public Optional<Child> child = Optional.empty();

        /**
         * Creates a new task.
         */
        protected AbstractTask()
                throws NullPointerException {
        }

        @Override
        public Optional<Child> getChild() {
            return child;
        }
    }

    public static final class Task1 extends AbstractTask<Task<?, ?>, Task2> {

        @JsonCreator
        public Task1()
                throws NullPointerException {
        }

        @JsonIgnore
        @Override
        public Optional<Task<?, ?>> getParent() {
            return Optional.empty();
        }
    }

    public static final class Task2 extends AbstractTask<Task1, Task3> {

        @JsonProperty
        private final Optional<Task1> parent;

        @JsonCreator
        public Task2(@JsonProperty("parent") Task1 parent)
                throws NullPointerException, IllegalArgumentException {
            this.parent = Optional.of(parent);
        }

        @Override
        public Optional<Task1> getParent() {
            return parent;
        }
    }

    public static final class Task3 extends AbstractTask<Task2, Task<?, ?>> {

        @JsonProperty
        private final Optional<Task2> parent;

        @JsonCreator
        public Task3(@JsonProperty("parent") Task2 parent)
                throws NullPointerException, IllegalArgumentException {
            this.parent = Optional.of(parent);
        }

        @Override
        public Optional<Task2> getParent() {
            return parent;
        }
    }

    public static void main(String[] args) throws IOException {
        ObjectMapper mapper = new ObjectMapper();

        // Pretty-printing
        mapper.enable(SerializationFeature.INDENT_OUTPUT);
        // java.util.Optional
        mapper.registerModule(new Jdk8Module());

        Task1 task1 = new Task1();
        Task2 task2 = new Task2(task1);
        Task3 task3 = new Task3(task2);
        task1.child = Optional.of(task2);
        task2.child = Optional.of(task3);

        File file = new File("target/test.xml");
        mapper.writeValue(file, task1);

        // This fails with: com.fasterxml.jackson.databind.deser.UnresolvedForwardReference: Could not resolve Object Id [2] (for [simple type, class Task2]).
        task1 = mapper.readValue(file, Task1.class);

        System.out.println("Success: " + task1);
    }
}