public void reduce(final Text key, final Iterable<Text> values, final Context context) throws IOException, InterruptedException {

    ArrayList commonFriends = new ArrayList();
    ArrayList allcommonFriends = new ArrayList();

    for (Text word : values) {
        //java.lang.String[] friends = word.toString().split(" ");//convert string to string array
        //commonFriends.add(friends);
        allcommonFriends.add(word.toString());
    }


    //if(values.size()!=2) System.out.println("Error");

        StringTokenizer list1 = new StringTokenizer( allcommonFriends.get(0).toString());
        StringTokenizer list2 = new StringTokenizer(allcommonFriends.get(1).toString());

        while (list1.hasMoreTokens()) {
        String friend1=list1.nextToken();
            while (list2.hasMoreTokens()) {
                String friend2=list2.nextToken();
                if(friend1 == friend2) commonFriends.add(friend1);
                }
        }
        }
        Collection<String> allValues= commonFriends.values();
        java.lang.String entireText = StringUtils.join(allValues, ',');

        friendList.set(entireText);
        context.write(key, friendList);