Please show code example JavaFX (GUI) and java under web what is the difference?

Question

Java

In the previous question, I was told that Java Destop and Java Web are different and the Destop developer will have to retrain on the Web, is this true? Maybe you have a sample code of the same application for an example? I just really want to see what the difference is.
Probably in packages, etc? But it's variables. methods are still the same.
Here is an example of console input
import java.util.Scanner
Modal windows
JOptionPane
Please explain if you have time! Thanks to!!!!!

Answer 1

The difference is in everything. There are not only different packages, there are even different architectural principles. The canonical example of a Spring web application is PetClinic . Same for JSF+EJB .

Answer 2

This topic is exhaustively described in the book "Clean Architecture" by Robert Martin. In particular, chapter 21 is devoted to the fact that the architecture of the application is not related in any way to the launch platform and the framework used.
Regarding "relearning between the desktop and the web" - it sounds like "relearning between a screwdriver and a hammer." Will you have to learn new tools? Undoubtedly. But this does not mean that the already mastered baggage of knowledge will become a burden. Both desktop and web and mobile development have a common denominator. And implementation details sooner or later replace each other, even within the same platform.