Issues while deserializing exception/throwable using Jackson in Java

Question

I am facing issues while deserializing Exception and Throwable instances using Jackson (version 2.2.1). Consider the following snippet:

public static void main(String[] args) throws IOException
{
    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
    objectMapper.setVisibility(PropertyAccessor.FIELD, Visibility.ANY);
    objectMapper.enableDefaultTyping(DefaultTyping.NON_FINAL, As.PROPERTY);

    try {
        Integer.parseInt("String");
    }
    catch (NumberFormatException e) {
        RuntimeException runtimeException = new RuntimeException(e);
        String serializedException = objectMapper.writeValueAsString(runtimeException);
        System.out.println(serializedException);
        Throwable throwable = objectMapper.readValue(serializedException, Throwable.class);
        throwable.printStackTrace();
    }
}

The output of System.out.println in the catch block is:

{
  "@class" : "java.lang.RuntimeException",
  "detailMessage" : "java.lang.NumberFormatException: For input string: \"String\"",
  "cause" : {
    "@class" : "java.lang.NumberFormatException",
    "detailMessage" : "For input string: \"String\"",
    "cause" : null,
    "stackTrace" : [ {
      "declaringClass" : "java.lang.NumberFormatException",
      "methodName" : "forInputString",
      "fileName" : "NumberFormatException.java",
      "lineNumber" : 65
    }, {
      "declaringClass" : "java.lang.Integer",
      "methodName" : "parseInt",
      "fileName" : "Integer.java",
      "lineNumber" : 492
    }, {
      "declaringClass" : "java.lang.Integer",
      "methodName" : "parseInt",
      "fileName" : "Integer.java",
      "lineNumber" : 527
    }, {
      "declaringClass" : "test.jackson.JacksonTest",
      "methodName" : "main",
      "fileName" : "JacksonTest.java",
      "lineNumber" : 26
    } ],
    "suppressedExceptions" : [ "java.util.ArrayList", [ ] ]
  },
  "stackTrace" : [ {
    "declaringClass" : "test.jackson.JacksonTest",
    "methodName" : "main",
    "fileName" : "JacksonTest.java",
    "lineNumber" : 29
  } ],
  "suppressedExceptions" : [ "java.util.ArrayList", [ ] ]
}

which seems fine. But when I attempt to deserialize this using objectMapper.readValue(), I get the following exception:

Exception in thread "main" com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "declaringClass" (class java.lang.StackTraceElement), not marked as ignorable
 at [Source: java.io.StringReader@3c5ebd39; line: 9, column: 27] (through reference chain: java.lang.StackTraceElement["declaringClass"])
    at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:79)
    at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:555)
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:708)
    at com.fasterxml.jackson.databind.deser.std.JdkDeserializers$StackTraceElementDeserializer.deserialize(JdkDeserializers.java:414)
    at com.fasterxml.jackson.databind.deser.std.JdkDeserializers$StackTraceElementDeserializer.deserialize(JdkDeserializers.java:380)
    at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:151)
...

I then tried using mix-in annotations, to ignore declaringClass in java.lang.StackTraceElement, but now the deserialized Exception doesn't contain the declaring class in its stack trace:

java.lang.RuntimeException: java.lang.NumberFormatException: For input string: "String"
    at .main(JacksonTest.java:33)
Caused by: java.lang.NumberFormatException: For input string: "String"
    at .forInputString(NumberFormatException.java:65)
    at .parseInt(Integer.java:492)
    at .parseInt(Integer.java:527)
    at .main(JacksonTest.java:30)

Am I missing anything? Any help is greatly appreciated.

Answer 1

It seems that the output you get in version 2.2.1 is not the same as I get with version 2.2.0 (which according to the website is the latest 2.x version). Besides the latest available 2.x version on the Maven Repository is 2.2.2. So I would try to either downgrade it to 2.2.0 or to upgrade it to 2.2.2. If any of the changes brings you the expected result, I would go further with that version and open a BUG in Jackson's JIRA.

And of course don't forget

objectMapper.configure( DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

from Michael's answer.

Answer 2

Try using polymorphism so that jackson deserializer knows what kind of Throwable to create:

/**
 * Jackson module to serialize / deserialize Throwable
 */
public class ThrowableModule extends SimpleModule {
  public ThrowableModule() {
    super("Throwable", new Version(1, 0, 0, null, null, null));
  }

  @Override
  public void setupModule(SetupContext context) {
    context.setMixInAnnotations(Throwable.class, ThrowableAnnotations.class);
  }

  /**
   * Add annotation to Throwable so that the class name is serialized with the instance data.
   */
  @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "class")
  static abstract class ThrowableAnnotations {
  }
}