@SuppressWarnings("unchecked") public String getResourceSubscriptionMD5(int resourceId) { MessageDigestGenerator md5Generator = new MessageDigestGenerator(); Query q = entityManager.createNamedQuery(Repo.QUERY_FIND_REPOS_BY_RESOURCE_ID); q.setParameter("resourceId", resourceId); List<Repo> repos = q.getResultList(); for (Repo repo : repos) { long modifiedTimestamp = repo.getLastModifiedDate(); Date modifiedDate = new Date(modifiedTimestamp); md5Generator.add(Integer.toString(modifiedDate.hashCode()).getBytes()); } String digestString = md5Generator.getDigestString(); return digestString; }