What components does a hash table data structure consist of and how does it work?

A hash table consists of two main components:

1. Array (bucket table) — a structure where elements are stored. Each index of the array is called a bucket.
2. Hash function — transforms a key into an array index (bucket), where the value will be stored.

How a hash table works:

• When adding a key-value pair, the key is passed through the hash function, which returns a bucket index.
• The value is placed in the bucket at this index.
• If multiple keys produce the same index (collision), a linked list or another structure within the bucket is usually used to store all elements with that index.

When searching for a key, the hash function calculates the index, and then the bucket is searched for the desired key.

Example in Java:

Map<String, Integer> map = new HashMap<>();
map.put("apple", 5);
int value = map.get("apple"); // 5

Here, HashMap implements a hash table where the key is a string, and the value is a number.