JsonProperty.Access.READ_ONLY not work

I want to disable one field deserialization, so first I add annotaion JsonProperty to the field, but it still throw exception in deserialization process.

Then I tried JsonIgnoreProperties, and annotate the class with specified field, jackson ignores the field and works as expected.

Below is the code:

// User.java
import com.fasterxml.jackson.annotation.JsonProperty;

import java.util.Arrays;
import java.util.List;

public class User {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @JsonProperty(access = JsonProperty.Access.READ_ONLY)
    public List<String> getRoles() {
        return Arrays.asList("admin", "monitor");
    }
}

// User1.java
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

import java.util.Arrays;
import java.util.List;

@JsonIgnoreProperties(value={ "roles" }, allowGetters=true)
public class User1 {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<String> getRoles() {
        return Arrays.asList("admin", "monitor");
    }
}

// AppTest.java
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.Test;

import static org.junit.Assert.assertTrue;

public class AppTest {
    @Test
    public void test1() throws Exception {
        User user = new User();
        user.setName("foo");
        ObjectMapper objectMapper = new ObjectMapper();
        String result;
        result = objectMapper.writeValueAsString(user);
        // will throw exception
        User deserizeUser = objectMapper.readValue(result, User.class);
    }

    @Test
    public void test2() throws Exception {
        User1 user = new User1();
        user.setName("foo");
        ObjectMapper objectMapper = new ObjectMapper();
        String result = objectMapper.writeValueAsString(user);
        assertTrue(result.contains("roles"));
        // Ok
        User1 deserilizeUser = objectMapper.readValue(result, User1.class);
    }
}

The first testcase will throw exception and it’s stacktrace is:

com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.UnsupportedOperationException) (through reference chain: kk.User["roles"]->java.util.Arrays$ArrayList[2])

	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:388)
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:360)
	at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:211)
	at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:20)
	at com.fasterxml.jackson.databind.deser.impl.SetterlessProperty.deserializeAndSet(SetterlessProperty.java:130)
	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.ObjectMapper._readMapAndClose(ObjectMapper.java:3814)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2858)
	at kk.AppTest.test1(AppTest.java:26)
	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 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:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.UnsupportedOperationException
	at java.util.AbstractList.add(AbstractList.java:148)
	at java.util.AbstractList.add(AbstractList.java:108)
	at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:198)
	... 29 more

[cowtowncoder]

Yes, it sounds like this might be due to conflict between “getter-as-setter” (only used for Collections) and READ_ONLY modifier. I agree in that READ_ONLY should work consistently and prevent assignment, as per Javadocs. So this sounds like a bug.

[cowtowncoder]

I just released 2.9.4 so it should now be available generally (for anyone else reading).