create an application class named letterdemo that instantiates objects of two classes named letter and certifiedletter and that demonstrates all their methods. the classes are used by a company to keep track of letters they mail to clients. the letter class includes auto-implemented properties for the name of the recipient and the date mailed (stored as strings).

You use the final keyword in a method declaration to indicate that the method cannot be overridden by subclasses. The Object class does this—a number of its methods are final .

What is object explain the class?

In computer programming, the object class refers to a class created to group various objects which are instances of that class. Classes are code templates for creating objects. In cases where objects need to be grouped in a certain way, an object class is the "container" for a set of objects built on these templates.
The following code is written in Java. It creates the three classes as requested with the correct constructors, and getter/setter methods. Then the test class asks the user for all the information and creates the customer object, finally printing out that information from the object getter methods.
Everything in Java is associated with classes and objects, along with its attributes and methods. For example: in real life, a car is an object. The car has attributes, such as weight and color, and methods, such as drive and brake. A Class is like an object constructor, or a "blueprint" for creating objects.

class Letter:

header="Dear "

footer="Sincerely, \n"

text=""

def __init__(self,letterFrom,letterTo):

self.header+=letterTo + ":\n\n"

self.footer+=letterFrom + "\n"

def getText(self):

return self.header+self.text+self.footer

def addLine(self,line):

self.text+=line+"\n\n"

l = Letter("Cain", "Abel")

l.addLine("I am very happy to be writing to you at this joyful moment of my life.")