[Java] Reflect:Class,Method,Field,Constructor...

1. Docs
2. Summary
   
   • Scan all methods, fields, and modified defiend in the specified classes
   • Create a new object
   • Invoke method
   • Change modified (such as public, private, protected)
     
3. Important Classes (Class + AccessibleObject)
   
   • Class
     Class is the in-memory representation of a Java class.
     
   • Constructor
   • Method
   • Field
   • Modifier
     
4. Change accessable (Access private method/field/constructor outside of class)
   Method method; //or Field/Constructor, it is private
   xxx;
   setAccessible(boolean flag);
   method.invoke(xxx);
   
5. Sample
   
   • getDeclaredMethod with primitive type
     (ref: )
     Method m = c.getDeclaredMethod("drinkMe", int.class);
     
   • Class cls = Class.forName("xxxx");
     Constructor[] array = cls.getConstructors();
   • xxx
     
6. xxx