A HashMap in Android is a data structure that stores key-value pairs. It is part of the Java Collections Framework and is implemented as a hash table. Here's how it works:
1. Hashing
When you add a key-value pair to a HashMap, the key is hashed using a hash function. The hash function converts the key into an integer, which is then used to determine the index where the key-value pair will be stored in the underlying array.
2. Collision Handling
Since multiple keys can hash to the same index, collisions can occur. HashMap uses separate chaining to handle collisions. Each index in the underlying array is associated with a linked list (or a tree, depending on the size of the list). When a collision occurs, the key-value pair is added to the linked list at the corresponding index.
3. Retrieving Values
To retrieve a value from the HashMap, the key is hashed using the same hash function. The resulting index is used to access the linked list at that index. The list is then traversed to find the key-value pair with the matching key.
