How does HashTable Handle HashCode Distribution in Java?

Key-value pairs that are mapped from keys to values using a hash function are stored in Java databases using hash tables. The distribution of hash codes, which guarantees effective element retrieval and storage, is one of a hash table's most important features.

In this article, we will learn about how HashTable handles hashcode distribution in Java.

HashTable handles HashCode Distribution

Java's Hash Table uses a hash function to map keys to indices in an array that stores the related data. The hash code of a key is calculated whenever a new key-value combination is created or whenever a key is used to retrieve a value. This hash code determines the index where the value will be stored or retrieved from. Efficient hash code distribution is crucial to prevent collisions, where two different keys produce the same hash code, leading to potential data loss or decreased performance.

Requirement:

It's essential to have a foundational knowledge of data structures and Java programming ideas before diving into Hash Tables in Java. It would also be helpful to understand how hash functions operate and how crucial they are for effectively storing and retrieving data.

Syntax

Hashtable<K, V> hashtable = new Hashtable<>();

Parameters and Return Value:

K: the type of keys in the Hash table
V: the type of values in the Hash table

Return Value: None

Techniques

The Hash Table class in Java manages the internal distribution of hash codes using a number of techniques, such as:

1. Using a good hash function: The Hash Table implementation in Java employs a well-crafted hash function to provide equally dispersed hash codes throughout the array indices.
2. Handle collisions: Java utilizes techniques like chaining (linked lists of key-value pairs at each index) or open addressing (identifying alternate slots) to handle collisions and assure efficient value retrieval in the event of hash code collisions, when several keys map to the same index.
3. Resizing: Java dynamically resizes the underlying array to maintain an appropriate load factor as the number of entries in the hash table rises, aiding in the distribution of hash codes.

HashTable Handle HashCode Distribution

Below is the implementation of HashTable to Handle HashCode distribution:

// Java Program for implementation of HashTable
// To Handle HashCode distribution
import java.util.Hashtable;

// Driver Class
public class HashTableExample {
      // main function
    public static void main(String[] args) {
        // Creating a Hashtable instance
        Hashtable<String, Integer> hashtable = new Hashtable<>();
        
        // Adding key-value pairs to the Hashtable
        hashtable.put("A", 1);
        hashtable.put("B", 2);
        hashtable.put("C", 3);
        
        // Retrieving values from the Hashtable
        System.out.println("Value for key 'A': " + hashtable.get("A"));
        System.out.println("Value for key 'B': " + hashtable.get("B"));
        System.out.println("Value for key 'C': " + hashtable.get("C"));
    }
}

Value for key 'A': 1
Value for key 'B': 2
Value for key 'C': 3

The Hash table in this problem distributes the hash codes of the keys "A," "B," and "C" in an efficient manner to guarantee quick retrieval of their respective values.