https://DevOpsCloud.io -- Cloud Monk Losang Jinpa, Ph.D., MCSE/MCT, GitOps DevOps Engineer

Java AbstractMap.keySet() is a method in the Java AbstractMap class that returns a set view of the keys contained in the map. The returned set is backed by the map, so changes to the map are reflected in the set and vice versa. Introduced in Java 1995 with Java 1.2, keySet() is commonly used for iterating over the keys in a map when the associated values are not immediately required.

https://docs.oracle.com/javase/8/docs/api/java/util/AbstractMap.html