java - Java抛出以下异常：找不到符号

Question

学习如何使用 JavaArrayLists它不断抛出以下异常：

496cc7/packlist.java:5: error: cannot find symbol List alist = new
ArrayList<>(); ^ symbol: class List location: class packlist 1 error

这对我来说是全新的，所以我不确定实际上出了什么问题，任何帮助将不胜感激

import java.util.ArrayList;
import java.util.Collections;
class packlist {
  public static void main(String args[]) {
    List <String> alist = new ArrayList<>();
    alist.add("Mark");
    alist.add("William");
    alist.add("John");
    alist.add("Dave");
    alist.add("James");
    System.out.println("The items of alist are: " + alist);
    Collections.reverse(alist);
    System.out.println("The reversed items of alist are: " + alist);
  }
}

预期的结果是的内容ArrayList，但反过来我得到了上面与第 5 行有关的错误

Answer 1

Add

import java.util.List;

and write

List<String> alist = new ArrayList<>();
//  ^
//  `-- no blank here

If you don't want to import List, use

ArrayList<String> alist = new ArrayList<>();