The main differences between ArrayMap and HashMap in Android are:
Memory usage: ArrayMap is more memory efficient than HashMap, especially for data structures containing up to a few hundred items[1][2][4]. ArrayMap uses two arrays internally - one for the keys and one for the values, avoiding the need for extra objects[1].
Time complexity: HashMap provides constant-time O(1) performance for get and put operations on average. In contrast, ArrayMap uses binary search on the internal arrays, resulting in O(log N) time complexity[1][4]. For small data sets (e.g. under 100 items), the performance difference is negligible[1].
Primitive key support: SparseArray and its specialized variants like SparseIntArray are recommended over HashMap when using primitive integer or long keys[4]. These specialized containers provide better perform...
