Parental delegation mechanism

JVM The parent delegation mechanism of

Leave it alone Give it to the parent class first Not until the top Then look for

Why is this design

Ensure that only one class instance template is in the method area

Prevent the core class library from being edited

1    SQL
2    springboot
3    maven
4    stream
5    lombok
6    mybatis
7    @WebFilter @ServletComponentScan @ComponentScan
8    explain Command to sql Slow query check
9    valueOf： First, the object will be judged to be non empty , If null Then return to "null" String does not throw NullPointerException
10    sun.misc.Unsafe class ,allocateInstance() Method to create an instance