java类加载和初始化_java静态变量什么时候初始化

package com.reflection;
 
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
 
public class Test03 { 
   
    public static void main(String[] args) throws Exception { 
   
        //获得class对象
        Class c1 = Class.forName("com.reflection.User");
        //1、构造一个对象，本质是无参构造器
        User user1 = (User) c1.newInstance();
        System.out.println(user1);
 
        //2、通过构造器创建对象
        Constructor constructor = c1.getDeclaredConstructor(int.class, String.class, int.class);
        User user2 = (User) constructor.newInstance(1,"郭一诺",1);
        System.out.println(user2);
 
        //3、通过反射调用普通方法
        User user3 = (User) c1.newInstance();
        Method setName = c1.getDeclaredMethod("setName", String.class);
        //invoke激活
        setName.invoke(user3,"素小暖");
        System.out.println(user3.getName());
 
        //4、通过反射操作属性
        User user4 = (User) c1.newInstance();
        Field name = c1.getDeclaredField("name");
        //true：取消Java语言访问检查
        name.setAccessible(true);
        name.set(user4,"素小暖2");
        System.out.println(user4.getName());
    }
}