Same properties are parsed multiple times when variable name is capitalized and JsonProperty annotated

I have created a repo for this bug. See here: https://github.com/dentych/jackson-bug

In short terms, the issue is that variables in caps (e.g. MAT) that is annotated with JsonProperty(“MAT”) will be in the serialized JSON string twice.

The example output from my reproduction: The POJO “MyCollection”:

class MyCollection {
    @JsonProperty("MAT")
    private MAT MAT = null;
    @JsonProperty("DAR")
    private DAR DAR = null;
    @JsonProperty("someString")
    private String someString = null;

    public MAT getMAT() {
        return MAT;
    }

    public void setMAT(MAT MAT) {
        this.MAT = MAT;
    }

    public DAR getDAR() {
        return DAR;
    }

    public void setDAR(DAR DAR) {
        this.DAR = DAR;
    }

    public String getSomeString() {
        return someString;
    }

    public void setSomeString(String someString) {
        this.someString = someString;
    }
}

MAT and DAR are two simple POJOs that includes a propery “String name”. Each have getter and setters for the string.

When parsed, the following is output:

value =
{
  "mat": {
    "name": "MAT object"
  },
  "dar": {
    "name": "DAR object"
  },
  "MAT": {
    "name": "MAT object"
  },
  "DAR": {
    "name": "DAR object"
  },
  "requestedBFE": "101262"
}

As you can see, MAT and DAR are both present as they should, but there’s also a mat and a dar that should not be present.

[cowtowncoder]

@dentych Thank you for verifying. This is the recommended way to deal with this situation then – for Jackson 3.0 we can and will change the defaults as well, to avoid having to configure mapper this way.

[dentych]

@cowtowncoder Using MapperFeature.USE_STD_BEAN_NAMING made it output the correct values and only once each.