eclipse无法导入java.util.Arrays包，附程序错误提示截图。

package com.imooc.collection; import java.util.ArrayList; import java.util.List; import java.util.Arrays; /* * * 备选课程类 */ public class ListTest { public List coursesToSelect; /* * * 用于存放备选课程的List */ public ListTest(){ this.coursesToSelect = new ArrayList(); } /* * * 用于往 coursesToSelect 中添加备选课程 */ public void testAdd(){ //创建一个课程对象，并通过调用add方法，添加到备选课程中 Course cr1 = new Course("1","数据结构"); coursesToSelect.add(cr1); Course temp =(Course) coursesToSelect.get(0); System.out.println("添加了课程："+temp.id+":"+temp.name); Course cr2 = new Course("2","C语言"); coursesToSelect.add(0,cr2); Course temp2 = (Course) coursesToSelect.get(0); System.out.println("添加了课程："+temp2.id+":"+temp2.name); // 以下方法会抛出数组下标越界异常 // Course cr3 = new Course("3","test"); // coursesToSelect.add(4,cr3); // 以下为出现错误，自己不会调试过来，"没有Arrays类" Course[] course = {new Course("3","离散数学"),new Course("4","汇编语言")}; coursesToSelect.addAll(Arrays.asList(course)); Course temp3 =(Course) coursesToSelect.get(2); Course temp4 =(Course) coursesToSelect.get(3); System.out.println("添加了两门课程："+temp3.id+":"+ temp3.name+";"+temp4.id+":"+temp4.name); // 同上问题，百度说是引入包不正常，但是已经引入了ArrayList包。 Course[] course2 = {new Course("5","高等数学"),new Course("6","汇编语言")}; coursesToSelect.addAll(2,Arrays.asLst(course2)); Course temp5 = (Course) coursesToSelect.get(2); Course temp6 = (Course) coursesToSelect.get(3); System.out.println("添加了两门课程："+temp5.id+":"+ temp5.name+";"+temp6.id+":"+temp6.name); } public void testGet(){ int size = coursesToSelect.size(); for(int i=0; i<size;i++){ Course cr = (Course) coursesToSelect.get(i); System.out.println("课程"+cr.id+":"+cr.name); } } public static void main( String[] args){ ListTest lt =new ListTest(); lt.testAdd(); lt.testGet(); } }