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

Java HashSet.contains() is a method in the Java HashSet class that checks whether a specified element exists in the set. It uses the Java equals() method to determine if an element is present, returning true if it finds the element, or false if it does not. Introduced in Java 1995 with Java 1.2, contains() is commonly used in Java applications to verify the existence of an element in a collection, particularly in sets where uniqueness is important.

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