public static void notEmpty(Collection collection) {
        notEmpty(collection,
                "[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
    }
Assert that a collection has elements; that is, it must not be
<code>null</code> and must have at least one element.
<pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
@param collection the collection to check
@throws IllegalArgumentException if the collection is <code>null</code> or has no elements
src/main/java/org/apache/shiro/lang/util/Assert.java