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

Java HashMap.merge() is a method in the Java HashMap class that combines a new value with an existing value for a given key using a remapping function. If the key does not exist, the new value is inserted into the map. Introduced in Java 2014 with Java 8, merge() is particularly useful for performing cumulative operations or consolidating data in maps.

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