HashMap is a funny name. The “hash” part refers to how it works internally; it really has nothing to do with how you use it.
But the “map” part is about what you’d think: it maps a key, which can be anything, to a value, which can also be anything.
Other languages might call this a dictionary, an associative array or some kind of associative memory. They all mean the same thing. With an array, you use an integer as the index. With a HashMap, you can use any object as the key, especially Strings (see Figure 2, A HashMap).
We’ll use this a lot in the plugins. It’s a great way to keep track of players, ...