Recommendation for boolean dataset with apache mahout
The code and data combination is too small for predicting a solution. But note that you will not get any answer if there are no recommendations made. In this case there will be no exception either. Looks like your code 

List&lt;RecommendedItem&gt; recommendations =
     recommender.recommend(userid, noOfRecommendations);


returned no recommendations. You should try with a variety of data.