src/main/java/org/jinstagram/http/URLUtils.java
public static String appendParametersToQueryString(String url, Map<String, String> params) {
        Preconditions.checkNotNull(url, "Cannot append to null URL");

        String queryString = URLUtils.formURLEncodeMap(params);

        if (queryString.equals(EMPTY_STRING)) {
            return url;
        } else {
            url += (url.indexOf(QUERY_STRING_SEPARATOR) != -1) ? PARAM_SEPARATOR : QUERY_STRING_SEPARATOR;
            url += queryString;

            return url;
        }
    }
public static String appendParametersToQueryString(String url, Map<String, String> params) {
        Preconditions.checkNotNull(url, "Cannot append to null URL");

        String queryString = URLUtils.formURLEncodeMap(params);

        if (queryString.equals(EMPTY_STRING)) {
            return url;
        } else {
            url += (url.indexOf(QUERY_STRING_SEPARATOR) != -1) ? PARAM_SEPARATOR : QUERY_STRING_SEPARATOR;
            url += queryString;

            return url;
        }
    }
Append given parameters to the query string of the url

@param url the url to append parameters to
@param params any map
@return new url with parameters on query string