Fetch Impl for relation

fetch.java

public void fetch(String association, Object entity) {
        if(association == null || entity == null){
        	return;
        }
        String hql = Utils.appendAll("SELECT n.", association, " FROM ", entity.getClass().getSimpleName(), " n WHERE n.id = :id").toString();
        Query query = em.createQuery(hql);
         try {
        	Object id = PropertyUtils.getProperty(entity, "id");
        	query.setParameter("id", id);
        	List<?> result = query.getResultList();
        	
        	Object associationType = PropertyUtils.getProperty(entity, association);
        	if (associationType instanceof Set<?>) {
        		@SuppressWarnings({ "unchecked", "rawtypes" })
				Set<?> localResult = new HashSet(result);
        		PropertyUtils.setProperty(entity, association, localResult);
        	}        		
        	else
        		PropertyUtils.setProperty(entity, association, result);
		} catch (Exception e) {
			throw new RuntimeException(e);
		}            		
	}