Hi,
I want to compute similarity measure between strings using wordnet, I run this code:

import java.io.FileInputStream;
import java.util.HashMap;
import java.util.Map;

import net.didion.jwnl.JWNL;
import shef.nlp.wordnet.similarity.SimilarityInfo;
import shef.nlp.wordnet.similarity.SimilarityMeasure;

public class wordnet
{

public static void main(String[] args) throws Exception 
{
//Initialize WordNet - this must be done before you try
        //and create a similarity measure otherwise nasty things
        //might happen!
        JWNL.initialize(new FileInputStream("test/wordnet.xml"));
       
        //Create a map to hold the similarity config params
        Map<String,String> params = new HashMap<String,String>();
       
        //the simType parameter is the class name of the measure to use
        params.put("simType","shef.nlp.wordnet.similarity.JCn");
       
        //this param should be the URL to an infocontent file (if required
        //by the similarity measure being loaded)
        params.put("infocontent","file:test/ic-bnc-resnik-add1.dat");
       
        //this param should be the URL to a mapping file if the
        //user needs to make synset mappings
        params.put("mapping","file:test/domain_independent.txt");
       
        //create the similarity measure
        SimilarityMeasure sim = SimilarityMeasure.newInstance(params);
       
        
        //get a similarity that involves a mapping
        SimilarityInfo d=sim.getSimilarity("english", "english");
        System.out.println(d.getSynset1());
        System.out.println(d.getSynset2());
        System.out.println(d.getSimilarity());
        System.out.println(d);

}

}

but I dont know why the result for the same strings is zero!!

result:
Jan 27, 2013 7:03:00 PM net.didion.jwnl.util.MessageLog doLog
INFO: Installing dictionary net.didion.jwnl.dictionary.FileBackedDictionary@48fbc0
[Synset: [Offset: 6074471] [POS: noun] Words: English -- (the discipline that studies the English language and literature)]
[Synset: [Offset: 6074471] [POS: noun] Words: English -- (the discipline that studies the English language and literature)]
0.0
english#n#3  english#n#3  0.0



Could you please help me?

Thanks in advance
Soodeh.