class Person implements Cloneable{
    String name;
    int age;

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

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

    public Person() {

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public Person clone() throws CloneNotSupportedException {
        return (Person) super.clone();
    }

    @Override
    public void finalize() throws Throwable {
        System.out.println("finalize...");
        super.finalize();
    }
}

public class SubPerson extends Person {
    String name;
    int age;

    @Override
    public String toString() {
        return super.toString()+"SubPerson{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}


public static void main(String[] args) {
    try {
        SubPerson person = new SubPerson();
        Field[] allFields = FieldUtils.getAllFields(person.getClass());
        int a = 10;
        for (Field field : allFields) {
            if(field.getName() == "age"){
                field.setAccessible(true);
                field.set(person, a++);
            }
        }
        System.out.println(person);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

输出结果:Person{name=‘null’, age=11}SubPerson{name=‘null’, age=10}