(A), the Java reflection mechanism

First, what is reflection?

　　After the loaded class, the method of heap memory area produces a Class object type (only one of a class Class object), the object contains information about the structure of the entire class. We can see the structure of the class through this object. This is called reflection. Reflection mechanism that allows programs acquired by any type of internal information during execution Reflection API, and internal properties and methods of any object can be directly operated.