Why was HashMap developed?

For efficient storage and quick access to data in key-value pairs. Unlike ArrayList or LinkedList, which require linear search (average O(n)), HashMap provides an average access time of O(1) for elements, thanks to hashing. It was developed as a standard implementation of the Map interface in the Java Collections Framework, offering an unordered set of elements where each key is unique. This is critical for tasks such as caching, data indexing, and implementing associative arrays.