Understand Java HashMap with a puzzle

How well do you know Java's HashMap? This puzzle defines a POJO class, uses it in a HashMap, and asks 5 true/false questions. I've been asking this question in interviews since 2018. Almost nobody has answered all correctly. Will you?

00:00 Introduction
00:37 The Person class
01:20 The puzzles
02:58 Explanation in brief
04:04 HashMap illustration and workings
05:24 Detailed explanation
06:51 Lessons

The entire video was typed using Robotonous available at https://github.com/lvijay/robotonous.
The voiceover was made using the Festival Speech Synthesis System: https://www.cstr.ed.ac.uk/projects/festival/ compiled for the Mac using GNU Make.