GSON : java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING

Question

I am facing a problem about the GSON json to Java. I looked up many posts here, but I cannot find the solution for my question. So I list my problem here. Thanks very much !

Here is my Json Data

"{
    "data": {
        "marks": "",
        "spines": "",
        "dendrites": {
            "voxel": [
                [383,382,382,381],
                [49,50,51,52],
                [7,10,10,10],
                [0,0,0,0]
            ],
            "maxint": [32,42,28,28],
            "maxintcorrected": null,
            "maxintcube": null,
            "medianfiltered": [54.36979745,54.36979745,54.36979745,54.36979745],
            "meanbacksingle": null,
            "maxintsingle": null,
            "thres": null,
            "meanback": 42,
            "index": 1,
            "length": [0,0.3223757885,0.6336712814,0.9350672197,1.227262867],
            "XYlength": [0,0.2085982964,0.410997367,0.6084466603]
        }
    }
}
"

My Class's defination is following

public class Test {
    public data data;

    public class data {

        public Object marks;
        public String spines = "";
        public StandardSpinenalysisImage.data.dendrites[] dendrites;

        public class dendrites {

            public int voxel[][];
            public int maxint[];
            public String maxintcorrected = "";
            public String maxintcube = "";
            public int medianfiltered[];
            public String meanbacksingle = "";
            public String maxintsingle = "";
            public int thres = 0;
            public int meanback;
            public int index = 0;
            public int length[];
            public int XYlength[];

            public dendrites() {
                this.thres = 100;
            }
        }
    }
}

But when I use the code Test t = g.fromJson(input, Test.class);

I got the error result.

Exception in thread "AWT-EventQueue-0" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 5

Thank you very very MUCH!!

Answer 1

your json looks good. just try remove the " from the beginning and the end of the json

you can try using this link to verify your json

Answer 2

Faced the same error today. In mine, the problem was one variable in JSON mapped to a String, but in the class the variable was on object of a Class Type. This made Gson think that the JSON variable should be of the Class Type, causing IllegalStateException with Expected BEGIN_OBJECT but was STRING

Hope it helps someone.