Is there any major difference between XAMPP and LAMP?

LAMP is an acronym for Linux (operating system), Apache HTTP Server, MySQL (database software), and PHP. If you're running Windows the acronym is WAMP.

XAMPP is a package you can use to easily install and configure a (in your case) WAMP or LAMP setup. If they are asking LAMP they probably expect some Linux and Apache knowledge, but it could also be they are just expecting a PHP programmer with MySQL skills. You'll find out what they're looking for in the job interview ;).

LAMP and WAMP are generic terms for any Apache web server, MySQL database, and Perl or PHP or Python language, based system.

XAMPP is a specific software package that contains all the elements of an *AMP system in a single package. There are several packages like this (WampServer to name one).

The software install process on Ubuntu is so straightforward that many people prefer to install the components individually and run a leaner and meaner setup.