eclipse中jsp代码里ArrayList报错

报错代码行：ArrayList students=(ArrayList)request.getAttribute("students");
报错内容：
Multiple annotations found at this line:
- Student cannot be resolved to
a type
- ArrayList cannot be resolved to
a type
有朋友了解吗？

对应的类没有引入吧

java.util.ArrayList students= (java.util.ArrayList)request.getAttribute("students");