public static boolean isEmpty(Collection c) {
        return c == null || c.isEmpty();
    }
Returns {@code true} if the specified {@code Collection} is {@code null} or {@link Collection#isEmpty empty},
{@code false} otherwise.

@param c the collection to check
@return {@code true} if the specified {@code Collection} is {@code null} or {@link Collection#isEmpty empty},
{@code false} otherwise.
@since 1.0
core/src/main/java/org/apache/shiro/util/CollectionUtils.java