jackson-module-kotlin: @JsonUnwrapped fails if parameter is non-nullable

I’ve made a commit onto my fork that demonstrates an error I’ve been trying to resolve for the whole day. It seems that JsonUnwrapped doesn’t work with non-nullable values.

If you run my commit, you’ll see that the first Boom does not fail, as Bomb? allows for null values (which are needed for some reason?), while Boom2 fails, with the error:

com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException: Instantiation of [simple type, class com.fasterxml.jackson.module.kotlin.test.TestCasesFromSlack1$Boom2] value failed for JSON property value due to missing (therefore NULL) value for creator parameter value which is a non-nullable type
 at [Source: 
           {
                "word": "HI"
            }
        ; line: 4, column: 13] (through reference chain: com.fasterxml.jackson.module.kotlin.test.TestCasesFromSlack1$Boom2["value"])

	at com.fasterxml.jackson.module.kotlin.KotlinValueInstantiator.createFromObjectWith(KotlinValueInstantiator.kt:44)
	at com.fasterxml.jackson.databind.deser.impl.PropertyBasedCreator.build(PropertyBasedCreator.java:138)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeUsingPropertyBasedWithUnwrapped(BeanDeserializer.java:779)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeWithUnwrapped(BeanDeserializer.java:605)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:309)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3837)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2899)
	at com.fasterxml.jackson.module.kotlin.test.TestCasesFromSlack1.testCzarSpringThing1(TestCasesFromSlack.kt:87)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

In addition, I’m running a test in my code that looks like this

public class JsonDeserializationTest
{

    MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();

    @Test
    public void allClassesUsedByOurControllersShouldBeDeserializableByJackson() throws Exception
    {
        assertCanBeMapped(OSValueObject.class);
        ......
        assertCanBeMapped(MoreValueObject.class);
    }

    private void assertCanBeMapped(Class<?> classToTest)
    {
        String message =
                String.format("%s is not deserialisable, check the swallowed exception in StdDeserializerProvider.hasValueDeserializerFor",
                       classToTest.getSimpleName());
        converter.getObjectMapper().findAndRegisterModules();
        assertThat(message, converter.canRead(classToTest, MediaType.APPLICATION_JSON), is(true));
    }

}

which fails if I don’t include @param:JsonProperty("data") on the element, like so:

data class OSValueObject(
        val oneId: OneId,
        val twoId: TwoId,
        @param:JsonProperty("details") @JsonUnwrapped val details: Details?
)

Error message:


java.lang.AssertionError: OSValueObject is not deserialisable, check the swallowed exception in StdDeserializerProvider.hasValueDeserializerFor
Expected: is <true>
     but: was <false>

	at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
	at com.company.loanapp.JsonDeserializationTest.assertCanBeMapped(JsonDeserializationTest.java:72)
	at com.company.loanapp.JsonDeserializationTest.allClassesUsedByOurControllersShouldBeDeserializableByJackson(JsonDeserializationTest.java:59)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

About this issue

  • Original URL
  • State: closed
  • Created 8 years ago
  • Reactions: 1
  • Comments: 15 (6 by maintainers)

Commits related to this issue

Most upvoted comments

@cowtowncoder yes, it is possible, less idiomatic but just fine. Will close now.

+4
apatrida on Feb 5, 2018

I can reproduce error with following data classes and json:

data class Name (val firstName: String, val lastName: String)

data class Employee ( @get:JsonProperty(“useless”) @get:JsonUnwrapped val name: Name, val position: String )

JSON: {“firstName”:“John”,“lastName”:“Smith”,“position”:“Manager”}

I’m using version 2.8.4 of jackson-kotlin-module.

+2
pvo99i on Dec 20, 2016

I’ve found workaround:

data class Name(val firstName: String, val lastName: String)

val JACKSON_WORKAROUND = Name(“”, “”)

data class Employee( @get:JsonProperty(“name”) @get:JsonUnwrapped val name: Name = JACKSON_WORKAROUND, val position: String )

+1
pvo99i on Dec 20, 2016
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