Parental delegation model [understanding]

Parental delegation model definition ：

• When a class loader receives a class loading task , I will first give it to my father loader to finish it , If the parent class cannot be loaded , Then continue upward , Finally reach the top （BootstrapClassLoader）, In the process , If already loaded , Then return to .
• To reach the vertex, you need to look down , Subclass to see if it can load , If it can be loaded, it returns , Otherwise, to the starting point , Report errors .

First of all, there are three classes of loaders ：

• 1、BootstrapClassLoader（ Top level class loader 、 Start class loader ）
• 2、ExtentionClassLoader（ Extended class loader ）
• 3、AppClassLoader（ Application class loader ）
  • It is recommended that the hard back has three loaders ,1 --> 2 --> 3 Express grandpa --> Dad --> I
  • We write our own classes and introduce JAR Packages usually start with this loader

Parental delegation is ：