使用Field中的set方法抛出IllegalArgumentException？？

[HJMing123]

代码如下，不是很懂为什么会抛出这个 异常？求教！！~~

class Student 
{
	public Student(){}
	
	public Student(String name, int age) {
		this.name = name;
		this.age = age;
	}

	private String name;
	private int age;
	
	public String getName()
	{
		return name;
	}
	public int getAge()
	{
		return age;
	}

}

public class Reflect {

	public static void main(String[] args) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException 
	{
		Student s =new Student("Sam",23);
		Class c = s.getClass();
		Field f= c.getDeclaredField("name");
		System.out.println(f);
		f.setAccessible(true);
		Object obj = f.get(s);
		System.out.println(obj);
		Field f1 =c.getDeclaredField("age");
		f1.setAccessible(true);
		Object obj1= f1.get(s);
		System.out.println(obj1);
		
		f.set(obj,"huhu");
		System.out.println(obj);
		
	}

}

[自由自在_Yu]

f.set(s,"huhu"); System.out.println(obj);