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

Java HashMap.containsKey() is a method in the Java HashMap class that checks if the map contains the specified key. It is used to verify whether a specific key exists before retrieving or updating its associated value. Introduced in Java 1995 with Java 1.2, containsKey() is commonly used to avoid NullPointerException and ensure the integrity of data retrieval in Java Map implementations.

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