Wrong exception reported in case of Name Mismatch

[revolutionisme]

Version information - "Jackson-databind - version 2.9.1"

Having enabled the property "UNWRAP_ROOT_VALUE" for deserialization as follows:

mapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE);

a simple json message like "{"TestMessage":"This test is awesome"}" is not parsed to a JsonNode when using

eventNode = this.mapper.readTree(message)

and getting the following exception:

Caused by: java.util.MissingFormatArgumentException: Format specifier '%s'
	at java.util.Formatter.format(Formatter.java:2519) ~[na:1.8.0_121]
	at java.util.Formatter.format(Formatter.java:2455) ~[na:1.8.0_121]
	at java.lang.String.format(String.java:2940) ~[na:1.8.0_121]
	at com.fasterxml.jackson.databind.DatabindContext._format(DatabindContext.java:326) ~[jackson-databind-2.9.1.jar:2.9.1]
	at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1341) ~[jackson-databind-2.9.1.jar:2.9.1]
	at com.fasterxml.jackson.databind.ObjectMapper._unwrapAndDeserialize(ObjectMapper.java:4076) ~[jackson-databind-2.9.1.jar:2.9.1]
	at com.fasterxml.jackson.databind.ObjectMapper._readTreeAndClose(ObjectMapper.java:4042) ~[jackson-databind-2.9.1.jar:2.9.1]
	at com.fasterxml.jackson.databind.ObjectMapper.readTree(ObjectMapper.java:2539) ~[jackson-databind-2.9.1.jar:2.9.1]
	at com.airplus.sid.iomDataImport.config.TestReceiver.receive(TestReceiver.java:49) ~[test-classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

Upon further debugging, it was found that in ObjectMapper class

String actualName = p.getCurrentName();
        if (!expSimpleName.equals(actualName)) {
            ctxt.reportInputMismatch(rootType,
                    "Root name '%s' does not match expected ('%s') for type %s",
                    actualName, expSimpleName);
        }

Basically, only 2 arguments are fed when 3 are expected.

Also, its a different issue, but why is it expecting the rootname to be "JSONNode" when it should get it from the Json itself?

[cowtowncoder]

I think this might be dup of #1771? It has been fixed for 2.9.2.

As to root name -- it is always based on expected type (either annotation @JsonRootName, or that missing, simple class name) or from explicit root name definition. So in this case that'd be based on declared type.
Feature does not mean simply dropping the outermost name.

Although to be honest I am not sure why one would want to enable that feature if reading as a tree, since tree operations would be more flexible and convenient for manipulating results.

[cowtowncoder]

Assuming it is dup and will be fixed with 2.9.2

[vmisra2018]

@cowtowncoder

.
I am getting weird error

com.fasterxml.jackson.databind.exc.MismatchedInputException: Root name 'status' does not match expected ('JsonNode') for type [simple type, class com.fasterxml.jackson.databind.JsonNode]
at [Source: (String)"{"status":"some message"}"; line: 1, column: 2] 

in already working code.
In our spring legacy code (not boot) , the change I did was to add jackson-dataformat-xml dependency [core and annotation were already there] . I required it for xml support. So I have :
${jackson.version}= 2.10.0

<dependency>
           <groupId>com.fasterxml.jackson.core</groupId>
           <artifactId>jackson-databind</artifactId>
           <version>${jackson.version}</version>
       </dependency>
       <dependency>
          <groupId>com.fasterxml.jackson.core</groupId>
          <artifactId>jackson-annotations</artifactId>
          <version>${jackson.version}</version>
       </dependency>
       <dependency>
           <artifactId>jackson-dataformat-xml</artifactId>
           <groupId>com.fasterxml.jackson.dataformat</groupId>
           <version>${jackson.version}</version>
       </dependency>

But suddenly old code started to give above error . And I have to replace readTree with ObjectReader readerFor.
For a sample response from external service which is as simple as

Why do I have to suddenly change from readTree to like below :

        ...
          //JsonNode rootNode = objectMapper.readTree(resultInJson);
           ObjectReader reader = objectMapper.readerFor(JsonNode.class).withoutRootName();
           JsonNode rootNode = reader.readValue(resultInJson);
           
       } catch (JsonProcessingException e) {
           LOGGER.warn(e, e);
       }
        ```

Objectmapper is being used in lits of places . So I am worried as to why I have to change existing code?
        
        
        

[cowtowncoder]

@vmisra2018 Please file a new issue explaining your problem.