关于java的类加载器

Question

public class Main {
    public static void main(String[] args) {
        System.out.println(String.class.getClassLoader());
        System.out.println(Main.class.getClassLoader());
    }
}

分别输出null和AppClassLoader，为什么String是null？自己写的类即classpath下的是通过AppClassLoader加载，jdk里的类是通过哪个加载器加载的？

Answer 1

String’s class loader is bootstrap class loader. Class loading in this way will be displayed as null

Answer 2

String is loaded by the bootstrap class loader, and 引导类加载器 is implemented in native C++ code and does not inherit from java.lang.ClassLoader. We cannot obtain this class loader in the program of.