reflection - method invoke

gistfile1.txt

package reflection;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

class Student {

    private String name;
    private int age = (int) (Math.random() * 20 + 20);

    public Student(String name) {
        setName(name);
    }

    @Override
    public String toString() {
        return "Name: " + name + ", age: " + age;
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        if (age >= 0 && age <= 100) {
            this.age = age;
        } else {
            this.age = 18;
        }
    }
}

class Program {

    public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {

        Student s = new Student("Alex");
        Class c = s.getClass();
        Class[] paramTypes = new Class[]{String.class};
        Method method = c.getMethod("setName", paramTypes);
        Object[] arg = new Object[]{"Vasya"};
        method.invoke(s, arg);
        System.out.println(s.getName()); // Vasya

    }
}