尝试:

tourists.removeAll(Collections.singleton(null));

阅读 Java API.对于不可变列表(例如使用 Arrays.asList 创建)，代码将抛出 java.lang.UnsupportedOperationException；有关详细信息，请参阅此答案.

Read the Java API. The code will throw java.lang.UnsupportedOperationException for immutable lists (such as created with Arrays.asList); see this answer for more details.