What does Set[] sets = new Set[]{setW, setX, setY, setZ}; in Java mean?

Question

I believe this is a set of integer hashsets, but I'm confused about why [] are used before and after the equals sign.

Answer 1

It is an array of sets, which means there are multiple sets of type Integer. In the given example you have 4 different sets combined in a single array. For accessing the first two sets you can write:

Set<Integer> setW = sets[0];
// Here you can work with setW
Set<Integer> setX = sets[1];
// Here you can work with setX
...

or you can use a loop for iterating the array and accessing all sets:

for (Set<Integer> set : sets) {
    set.forEach(System.out::println);
}