code: public static <T> Collection<T> notEmpty(Collection<T> collection) throws IllegalArgumentException {
  		return notEmpty(collection, "[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
  	}
docs: 断言给定集合非空
  
  <pre class="code">
  Assert.notEmpty(collection);
  </pre>
  
  @param <T> 集合元素类型
  @param collection 被检查的集合
  @return 被检查集合
  @throws IllegalArgumentException if the collection is {@code null} or has no elements