how to achieve page factory code example

Example 1: why page object model

Pom basically Creating java classes
for the each page of our application,
and storing related webelements,
and methods in their respective classes.
    
Advantages of POM =
First of all, it makes our code REUSABLE.
I don't have to repeatedly locate web elements
in every single other class.
Secondly it is EASY TO MAINTAIN. I store one
webelement in one class and it is a lot easier to
fix any issue with that web element because I know
exactly where everything is stored.
Thirdly is seperating webelements and our test cases.
Our test cases will be cleaner therefore 
easy to manage overall.

HOW I CREATE POM =  
#1-I Create constructor, 
and pass PageFactory.initElements(objectOfClass, Driver)
#2- I use @FindBy annotation to locate web elements
            - FindBy annotation comes from Selenium.

Example 2: what is page factory

PageFactory is a class in selenium. 
It is used to achieve page factory design pattern, 
it helps to initialize the page objects in the
class using initElements methods. When 
I create an object from the page class,
pagefactory initializes the webelements 
just before interacting this web element.
It means that once you call the element, 
PageFactory class will immediately locate the element
and you will not get a staleElementReferenceException. 

When a page object is created, 
pagefactory driver (because of the constructor)
will be linked to weblements @findby in that page.

 public LoginPage(){
        PageFactory.initElements(Driver.get(), this);
    }