ArrayIndexOutOfBoundsException in instance classification in java using weka

Question

I am writing a program to classify a given test instance in to "positive" or "negative"; using j48 algorithm. I have created the model using Weka tool, and using it in my java program.

My Java program

public static void main(String[] args) {

        double result = -1;

        try {

            ArrayList<Attribute> attributeList = new ArrayList<>(2);

            Attribute tweet = new Attribute("tweet", true);

            ArrayList<String> classVal = new ArrayList<>();

            classVal.add("positive");
            classVal.add("negative");

            attributeList.add(tweet);
            attributeList.add(new Attribute("class", classVal));

            Instances data = new Instances("TestInstances", attributeList, 1);
            Instance inst_co = new DenseInstance(data.numAttributes());
            data.add(inst_co);
            data.setClassIndex(data.numAttributes() - 1);  

            inst_co.setValue(tweet, "I love my grandmom");

            StringToWordVector filter = new StringToWordVector();

             Classifier cls_co = (Classifier) weka.core.SerializationHelper
                    .read("G:/love.model");

            result = cls_co.classifyInstance(data.firstInstance());

            System.out.println(result);

        } catch (Exception e) {

             System.out.println(e.getMessage());
        }

    }

My training data file

@RELATION love

@ATTRIBUTE tweet string
@ATTRIBUTE class {positive,negative}

@DATA

"I love my sister", positive
"I love my brother", positive
"I love my father", positive
"I love my mother", positive
"I love my uncle", positive
"I love my grandmom", positive
"I hate my cats", negative
"I hate my car", negative
"I hate my van", negative
"I hate my rice", negative
"I hate my bun", negative

I am getting an ArrayIndexOutOfBoundsException from result = cls_co.classifyInstance(data.firstInstance());

I tried many examples found on the internet. But still I am getting the same error.

Thanks in advance.