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

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