11- parent class loader delegation mechanism Detailed

Parent class loader delegation mechanism Detailed

• In the parent delegation mechanism, each class loader in accordance with parent-child relationships forming a tree structure (actually a logical relationship comprising a), except the root class loader, the rest of the class loader has one and only one parent loader .

• If a class loader loads successfully Test classes, then the class loader is referred defined class loader , all return Class successfully applied to the object class loader (including custom class loader) are called the initial class loader . [Pictured above, the system class loader can be referred to: define a class loader, class loading system and can be called loader1: initial class loader]

  • Example:

    public class MyTest7 {
        public static void main(String[] args) throws ClassNotFoundException {
            Class<?> clazz1 = Class.forName("java.lang.String");
            System.out.println(clazz1.getClassLoader());
    
            Class<?> clazz2 = Class.forName("Jvm.D");
            System.out.println(clazz2.getClassLoader());
        }
    }
    class D{
    
    }
    运行结果：
       null  --》 就根类加载器
       sun.misc.Launcher$AppClassLoader@18b4aac2 --》AppClassLoader，就是系统类加载器