Program to classify data using weka tool

package weka.api;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import weka.classifiers.trees.J48;
import weka.core.Instances;

public class Classify{
public static void main(String[] args) throws Exception
{
    BufferedReader breader = null;
   
    breader = new BufferedReader(new FileReader("/home/sonali/11.arff"));

    Instances train = new Instances(breader);
    train.setClassIndex(train.numAttributes() -1);
    breader = new BufferedReader(new FileReader("/home/sonali/22.arff"));
    Instances test = new Instances(breader);
   
    test.setClassIndex(train.numAttributes() -1);
    breader.close();
   
     J48 tree = new J48();
   
    tree.buildClassifier(train);
       
    Instances labeled = new Instances(test);
     
   
    for(int i=0;i< test.numInstances();i++)
    {
        double clsLabel = tree.classifyInstance(test.instance(i));
        labeled.instance(i).setClassValue(clsLabel);
       
     }
    BufferedWriter bwriter =  new BufferedWriter(
            new FileWriter("/home/sonali/labeled1.arff"));
    bwriter.write(labeled.toString());
    bwriter.close();
  }
}


Steps to run the program -