JsonMappingException with jackson-databind version 2.8.0 and higher

[Anuj Kumar]

I am getting an exception with jackson databind version 2.8.0 and later, everything works fine with any version below 2.8.0. 

Issue is, if I have a property name with an underscore and the letter after it is NOT the same as the first letter, then things blow up.

For example I have a Person class which contains a Set<Person> which has the name as "person_z" which fails. 

But if I rename it to "person_p" it works.

public class Person {
    @JsonProperty("name")
    private String name;
    @JsonProperty("person_z") // renaming this to person_p works
    @JsonIgnoreProperties(value = {"person_z"}) // renaming this to person_p works
    private Set<Person> personZ;
}

public class TestJackson {

    public static void main(String[] args) throws IOException {

        String st =" [ {\n"
                + "    \"name\": \"admin\",\n"
                + "    \"person_z\": [" // renaming this to person_p works
                + "      {"
                + "        \"name\": \"admin\""
                + "      }"
                + "    ]"
                + "  }]";

        ObjectMapper mapper = new ObjectMapper();
        mapper.readValue(st, mapper.getTypeFactory().constructCollectionType(List.class, Person.class));
    }

}

Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: No _valueDeserializer assigned
 at [Source:  [ {
    "name": "admin",
    "person_z": [      {        "name": "admin"      }    ]  }]; line: 3, column: 41] (through reference chain: java.util.ArrayList[0]->com.example.Person["person_z"]->java.util.HashSet[0]->com.example.Person["name"])
	at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:261)
	at com.fasterxml.jackson.databind.DeserializationContext.reportMappingException(DeserializationContext.java:1233)
	at com.fasterxml.jackson.databind.deser.impl.FailingDeserializer.deserialize(FailingDeserializer.java:27)
	at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:490)
	at com.fasterxml.jackson.databind.deser.impl.FieldProperty.deserializeAndSet(FieldProperty.java:101)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:277)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:249)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26)
	at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:490)
	at com.fasterxml.jackson.databind.deser.impl.FieldProperty.deserializeAndSet(FieldProperty.java:101)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:277)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:249)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3789)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2871)
	at com.example.TestJackson.main(TestJackson.java:28)
	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:498)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

[Tatu Saloranta]

Could you please file an issue for `jackson-databind`. Looks like a bug.

-+ Tatu +-

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