Nullability
As we said, some elements in Kotlin can be assigned a value of null, and some cannot. We say that the former are nullable and the latter are non-nullable.
Null is not the same as zero or a statement of no value. Think about your bounty board. In the context of a fantasy game, the bounty board likely manifests as a literal bulletin board with quests on it. There is a difference between the board not having a quest (in other words, having a null value) and having a message that says “There are no quests right now.”
While null and “There are no quests right now.” might be interpreted in the same way, they have different implications.
A value of null signifies that nothing is present: There are no quests, there is no message ...
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