代码出错，。。

package com.imooc.collection;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.Scanner;

public class SetTest {

public List<Course>coursesToSelect;

public SetTest()

{

coursesToSelect=new ArrayList<Course>();

}

public void testAdd()

    {

    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);

    //coursesToSelect.add(cr1);

    //Course temp0=(Course)coursesToSelect.get(2);

    //System.out.println("添加了课程:"+temp.id+":"+temp.name);

    // Course cr3=new Course("3","test");

    //coursesToSelect.add(4,cr3);

    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(3);

    Course temp4=(Course)coursesToSelect.get(4);

    // System.out.println("添加了两门课程:"+temp3.id+";"+temp3.name+";"+temp4.id+";"+temp4.name);

     Course[] course2={new Course("5","高等数学"),new Course("6","大学英语")};

     coursesToSelect.addAll(2,Arrays.asList(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 testForEach()

     {

    System.out.println("有如下课程待选(通过foreach的方法):");

    for(Object obj:coursesToSelect)

    {

    Course cr=(Course)obj;

    System.out.println("课程:"+cr.id+":"+cr.name);

    }

     }

public static void main(String[] args) {

// TODO Auto-generated method stub

         SetTest st=new SetTest();

         st.testAdd();

         st.testForEach();

         Student student=new Student("1","小明");

         System.out.println("欢迎学生:"+student.name+"选课");

         Scanner console=new Scanner(System.in);

         for(int i=0;i<3;i++)

         {

        System.out.println("请输入课程ID");

        String courseId=console.next();

        for(Course cr:st.coursesToSelect)

        {

        if(cr.id.equals(courseId))

        {

        student.courses.add(cr);

        }

        }

         }

        st.testForEachForSet(student);  

}

  public void testForEachForSet(Student student)

    {

    for(Course cr:student.courses)

        {

        System.out.println("选择了课程:"+cr.id+":"+cr.name);

        }

    }

}

求解？？