BitSets are simply a growable bunch of bits. This can often be based on a simple binary integer number (i.e. byte, short, int or long in Java), or a specialized class like a BitSet or BigInteger. At Adligo we categorize BitSets as a growable essentially unbounded bunch of bits, this is because of the BitSet and BigInteger implementation in Java.
This was renamed by Scott from BitArrays on 2025-11-29 because of the growable attribute which seemed to conflict with Adligo’s Arrays#1.3.6.1.4.1.33097.1.1.0 definition. So he decided to move closer to the Java definition.
https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/math/BigInteger.html
https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/util/BitSet.html
https://en.wikipedia.org/wiki/Bit_array
https://docs.rs/bitvec/latest/bitvec/
https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/util/BitSet.html