通过反射攻击单例

import java.lang.reflect.Constructor;

public class Test {
    public static void main(String[] args) {
        try {
            Class<Runtime> clazz = Runtime.class;
            Constructor<Runtime> constructor = clazz.getDeclaredConstructor();
            constructor.setAccessible(true);
            constructor.newInstance();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}