Revolut interview question

What are SOLID, ACID, TDD, why unit tests are important? Then there was a code test to develop a rough Load Balancer, in which the idea is to receive a Collection of URLs in the constructor of a class and then validate duplication of URLS, number of URLs, and so on. If you take a little longer in any of the code implementations, you will be disqualified, so be sure to finish them as quickly as possible. Break down the code into separated methods and have your Java 11 with JUnit 5 created beforehand for the interview. If you don't use Java 11 methods you can be also disqualified. Make questions, and don't assume anything, the interviewer will know about the requirements of the problem.