An example adding behavior to a class
This example was used in Java Programming Basics by Simon Roberts - an O'relly course.
In this code it is possible to set a meeting date, with date, month and year.
But how can we solve a problem when we need to change the date of a meeting? Would you add a day to the date?
What would happen if you had a meeting on February 28, 2023 and decided to move to the next day?
February 29, 2023 does not exist!
A feature needs to be added to implement this validation... that's what was done.