Immutables: Cannot deserialize List with Jackson JDK 8

[rkuzsma]

I'm unable to @JsonDeserialize using List, but I am able to @JsonDeserialize using Collection.

Test case:

import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import org.immutables.value.Value;

import java.util.Collection;
import java.util.List;

@Value.Immutable
@JsonDeserialize(as = ImmutableA.class)
public abstract class A {

  // List<Foo> fails to deserialize. Error message given:
  // Can not find a deserializer for non-concrete Collection type
  //  [collection type; class com.google.common.collect.ImmutableList, 
  //   contains [simple type, class com.browserup.runDefinition.A$Foo]]
  @JsonProperty("foos")
  public abstract List<Foo> foos();

  // Collection<Foo> can deserialize without error:
  // public abstract Collection<Foo> foos();

  @Value.Immutable
  @JsonDeserialize(as = ImmutableFoo.class)
  public static abstract class Foo {
    @JsonProperty("id")
    public abstract Integer id();
  }

  public static void main(String[] args) throws Exception {
    String data = "{ \"foos\": [ { \"id\": 0 } ] }";
    ObjectMapper mapper = new ObjectMapper();
    A a = mapper.readValue(data, ImmutableA.class); // Fails
  }
}

[elucash]

There are 2 options how to handle it. The first option is to use jdkOnly=true style attribute to generate collection attributes without using Guava collections. The second option is to register module to handle Guava types https://github.com/FasterXML/jackson-datatype-guava . Just to mention, for java8 types there's similar module https://github.com/FasterXML/jackson-datatype-jdk8.
Hope this helps, thank you!

[rkuzsma]

Adding @Value.Style(jdkOnly=true) to the top of the class worked.
Using the jackson-datatype-jdk8 module did not work for me. I registered the module using:
mapper.registerModule(new Jdk8Module());
While the JDK8 module helps for resolving Optional types, it doesn't have any impact on List types.
I'll proceed using the jdkOnly types approach.

Thank you so much Eugene!

[elucash]

I hope this works for you, I also checked that mentioned https://github.com/FasterXML/jackson-datatype-guava should also work if you stick with Guava collection. Jdk-only is also a good choice, so you can mix and match.

[vijays2017]

Worked for me with JdkOnly=true. Thanks !