public static void notEmpty(Map map, String message) {
        if (isEmpty(map)) {
            throw new IllegalArgumentException(message);
        }
    }
Assert that a Map has entries; that is, it must not be <code>null</code>
and must have at least one entry.
<pre class="code">Assert.notEmpty(map, "Map must have 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</code> or has no entries
src/main/java/org/apache/shiro/lang/util/Assert.java