code: public static void notEmpty(Map<?, ?> map, String message) {
  		if (CollectionUtils.isEmpty(map)) {
  			throw new IllegalArgumentException(message);
  		}
  	}
docs: Assert that a Map contains entries; that is, it must not be {@code null}
  and must contain at least one entry.
  <pre class="code">Assert.notEmpty(map, "Map must contain entries");</pre>
  @param map the map to check
  @param message the exception message to use if the assertion fails
  @throws IllegalArgumentException if the map is {@code null} or contains no entries