Not able to store value getting from Transliteration using GWT - gwt

Question

I am new to GWT and I want to make a application in which words are transliterate and store in a varible.which can be used for storing values in database.
But when I am trying to store in variable it gives null value when am printing it.
package com.google.gwt.language.sample.hellolanguage.client;
import java.util.ArrayList;
import java.util.List;
import com.google.gwt.language.client.transliteration.LanguageCode;
import com.google.gwt.language.client.transliteration.SupportedDestinationLanguages;
import com.google.gwt.language.client.transliteration.control.TransliterationControl;
import com.google.gwt.language.client.transliteration.control.TransliterationControlOptions;
import com.google.gwt.language.client.transliteration.text.Transliteration;
import com.google.gwt.language.client.transliteration.text.TransliterationCallback;
import com.google.gwt.language.client.transliteration.text.TransliterationResult;
import com.google.gwt.user.client.ui.Composite;
public class Trans extends Composite {
ArrayList<String> wordsArray= new ArrayList<String>();
public String sss;
public void recieve(String ss)
{
this.sss=ss;
System.out.println(sss);
}
public String send(){
return sss;
}
public Trans(ArrayList<String> str) {
initTransliterationControls(str);
//Here I want to print
System.out.println(sss);
}
public void initTransliterationControls(ArrayList<String> wordsArray1) {
//ArrayList<String> wordsArray= new ArrayList<String>();
// wordsArray=wordsArray1;
//System.out.println(wordsArray1.size());
// for(int i=0;i<wordsArray1.size();i++)
//{
//wordsArray.add(wordsArray1.get(i).toString());
//}
wordsArray.add(wordsArray1.get(0).toString());
wordsArray.add("Rerrebok");
wordsArray.add("Woodland j_74_Hi-gh Heels Boots");
//System.out.println(wordsArray);
Transliteration.transliterate(wordsArray, LanguageCode.ENGLISH,
LanguageCode.HINDI, new TransliterationCallback() {
#Override
public void onCallback(TransliterationResult result) {
// System.out.println(result.getTransliterations().toString());
List<List<String>> collection= new ArrayList<List<String>>();
collection=result.getTransliterations();
// Here I am storing it on sss but when I am print outside this function it gives Null
sss=collection.get(0).get(0).toString();
}
});
}
}