Cannot deserialize value of type `java.lang.String` from Object value

[Prajwalgn-07]

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Serverless Java Container version: 2.0.1

Implementations: Spring Boot

Framework version: SpringBoot 3.2.4

Frontend service: REST API

Deployment method: Serverless Framework

Scenario

Describe what you are trying to accomplish

Hello I am creating a lambda function for my service. when I try to call my post API with the json body from lambda test console it is not able to deserialize it into the object which is defined in my code

Expected behavior

Describe how you would expect the application to behave
When I pass the body as json input it should get deserialized and consumed in my spring boot application

Actual behavior

Describe what you are seeing instead
It is throwing java.lang.String from Object value

Steps to reproduce

*Provide code samples we can use to reproduce the issue as part of our integration tests. If there is a public repository for the misbehaving application link to it here

Below is the test input given

{
  "resource": "/{proxy+}",
  "path": "/api/v1/inference",
  "body": {
    "model":"sketch",
    "sketch":{
    "params": {
        "seed": 12345,
        "max_seq_length": 512,
        "temperature": 1.0,
        "top_k": 1.0,
        "top_p": 0.5
    },
    "sketch": {
        "version": "4.0.0",
        "metadata": {
            "parent_project": "simple_11f5627d",
            "document_name": "Untitled",
            "component_name": "Untitled",
            "component_hierarchy": []
        },
        "name": "Test1",
        "type": "Sketch"
    }
    }
},
  "headers": {
    "Authorization": "Bearer <Removed Token>"
  },
  "httpMethod": "POST",
  "requestContext": {
   <Removed this since its not necessary for the issue>
  }
}

StreamLambdaHandler

public class StreamLambdaHandler implements RequestStreamHandler {
    private static final Logger logger = LoggerFactory.getLogger(StreamLambdaHandler.class);

    private static final SpringBootLambdaContainerHandler<AwsProxyRequest, AwsProxyResponse> handler;
    static {
        try {
            logger.info("Initializing SpringBootLambdaContainerHandler"+AwsProxyRequest.class);
            handler = SpringBootLambdaContainerHandler.getAwsProxyHandler(ServiceApplication.class);
        } catch (ContainerInitializationException e) {
            e.printStackTrace();
            throw new RuntimeException("Could not initialize Spring Boot application", e);
        }
    }

    @Override
    public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context)
            throws IOException {
        logger.info("Handling request"+inputStream.toString());
        handler.proxyStream(inputStream, outputStream, context);
    }
}

Rest Mapping

    @PostMapping("/inference")
    public ServiceResponse modelInference(@RequestBody ServiceRequest serviceRequest, @RequestHeader Map<String, String> headers) {
    ......

Full log output

Paste the full log output from the Lambda function's CloudWatch logs

Below is the stack trace

2024-04-20T09:41:05.847+05:30	at com.amazonaws.services.lambda.runtime.api.client.AWSLambda.startRuntime(AWSLambda.java:197) ~[aws-lambda-java-runtime-interface-client-2.4.2-linux-x86_64.jar:2.4.2]
2024-04-20T09:41:05.847+05:30
at com.amazonaws.services.lambda.runtime.api.client.AWSLambda.main(AWSLambda.java:187) ~[aws-lambda-java-runtime-interface-client-2.4.2-linux-x86_64.jar:2.4.2]

at com.amazonaws.services.lambda.runtime.api.client.AWSLambda.main(AWSLambda.java:187) ~[aws-lambda-java-runtime-interface-client-2.4.2-linux-x86_64.jar:2.4.2]
2024-04-20T09:41:05.848+05:30
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.lang.String` from Object value (token `JsonToken.START_OBJECT`)

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.lang.String` from Object value (token `JsonToken.START_OBJECT`)
2024-04-20T09:41:05.848+05:30	at [Source: (ByteArrayInputStream); line: 1, column: 59] (through reference chain: com.amazonaws.serverless.proxy.model.AwsProxyRequest["body"])
2024-04-20T09:41:05.848+05:30
at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)

at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1752)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1526)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1431)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.DeserializationContext.extractScalarFromObject(DeserializationContext.java:943)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.std.StdDeserializer._parseString(StdDeserializer.java:1424)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:48)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:11)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.module.afterburner.deser.SettableStringMethodProperty.deserializeAndSet(SettableStringMethodProperty.java:41)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:278)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.module.afterburner.deser.SuperSonicBeanDeserializer.deserialize(SuperSonicBeanDeserializer.java:155)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
2024-04-20T09:41:05.848+05:30	at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2105)
2024-04-20T09:41:05.849+05:30	at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1481)
2024-04-20T09:41:05.849+05:30	at com.amazonaws.serverless.proxy.internal.LambdaContainerHandler.proxyStream(LambdaContainerHandler.java:257)
2024-04-20T09:41:05.849+05:30	at com.<Removed>.StreamLambdaHandler.handleRequest(StreamLambdaHandler.java:36)

[Prajwalgn-07]

And yeah I tried setting the body value to string instead of the json input, and set the header

  "headers": {
    "Authorization": "Bearer <Removed Token>",
    "Content-Type": "application/json"
  }

Then I am getting the HttpMediaTypeNotSupportedException which doesn't make sense

START RequestId: 1f2fab44-1d58-47a9-bad9-d9718ef5b497 Version: 3
2024-04-21T12:44:04.309Z  WARN 8 --- [fusion-ai-service] [           main] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.web.HttpMediaTypeNotSupportedException: Content-Type 'application/octet-stream' is not supported]
2024-04-21T12:44:04.309Z  INFO 8 --- [fusion-ai-service] [           main] c.a.s.p.internal.LambdaContainerHandler  : 127.0.0.1 null- null [09/04/2015:12:34:56Z] "POST /api/v1/inference HTTP/1.1" 415 - "-" "Custom User Agent String" combined
END RequestId: 1f2fab44-1d58-47a9-bad9-d9718ef5b497
REPORT RequestId: 1f2fab44-1d58-47a9-bad9-d9718ef5b497	Duration: 3.40 ms	Billed Duration: 4 ms	Memory Size: 512 MB	Max Memory Used: 154 MB	

And yeah I tested by locally bringing up the service using sam and . there it seems to be working fine

[mbfreder]

Thanks for raising this. We will look into it.

[Vandita2020]

Hey @Prajwalgn-07,
I have tried to reproduce your issue and figure out the cause. In this case I think the issue is with your JSON file, and you were almost on the right path. You need to keep your body value to String instead of json. And you have to set content-type in multiValueHeaders instead of headers, something like mentioned below will work.

"multiValueHeaders":{
    "content-type":["application/json"]
  },

Please set this and let us know if you still get errors.