import java.util.Arrays; import java.util.Comparator; import java.util.Scanner; class Student{ String name; String id; int age; public Student() { } public Student(String name,String id,int age) { this.name=name; this.id=id; this.age=age; } } public class StaticTest { public static void main(String[] s) { Scanner sc=new Scanner(System.in); Student[] stu; for(int i=0;i
() { @Override public int compare(Student o1, Student o2) { // TODO Auto-generated method stub return o1.age-o2.age; } }); } } 此段代码是想完成对一个输入个数的Student数组进行排序,程序运行出现NullPointerException的异常,原因是: