输入问题？

Question

package com;
import java.util.*;public class testSortedSet {
static final Student students[]={
new Student("John","Lennon",14),
new Student("Karl","Marx",15),
new Student("Groucho","Bush",12),
new Student("Oscar","Grouch",13)

};
  /**
 * @param args
 */
public static void main(String[] args) {
// TODO Auto-generated method stub
List st =Arrays.asList(Students);
SortedSet stSet =new TreeSet(st);
System.out.println(stSet);

Student firstst=(Student)stSet.first();
System.out.println("first:"+firstst);

Student lastst=(Student)stSet.last();
System.out.println("last:"+lastst);

SortedSet headset=stSet.headSet(students[1]);
System.out.println("headSet:"+headset);

SortedSet tailset =stSet.tailSet(students[1]);
System.out.println("tainlSet:"+tailset);

SortedSet subset =stSet.subSet(students[2], students[0]);
System.out.println("subSet:"+subset);
}
}
Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
Students cannot be resolved
Student cannot be resolved to a type
Student cannot be resolved to a type
Student cannot be resolved to a type
Student cannot be resolved to a type
students cannot be resolved
students cannot be resolved
students cannot be resolved
students cannot be resolved at com.testSortedSet.main(testSortedSet.java:19)         怎么加Student类？使它可以运行

Answer 1

你连Student类都没创建，怎么定义这个变量和引用这个对象static final Student students[]={
new Student("John","Lennon",14),
new Student("Karl","Marx",15),
new Student("Groucho","Bush",12),
new Student("Oscar","Grouch",13)

};class Student{
     
     private String a;
     private String b;
     int c;
     public Student(String a , String b , int c){          this.a = a;
          this.b = b;
          this.c = c;     }}

Answer 2

List st =Arrays.asList(Students);你这个括号里，输的是什么？是类型啊？要小写Ｓ那是个变量，要引用．

Answer 3

Student firstst=(Student)stSet.first();
System.out.println("first:"+firstst);
连这个类都没，还强制转换类型，你下面全错了，