How is the storage and processing of elements with the same hash code implemented in the HashMap data structure?

Elements with the same hash code (collisions) in a HashMap are handled using chaining or other collision resolution methods. In the classic Java HashMap implementation, a linked list or a tree (if there are many elements with the same hash code) is used.

When two keys have the same hash code, they are placed in the same "bucket." During search or insertion, elements in this bucket are traversed, comparing keys using the equals() method to find the desired element.

Simplified example:

int bucketIndex = hash(key) % table.length;
Node current = table[bucketIndex];
while (current != null) {
    if (current.key.equals(key)) {
        // element found
        break;
    }
    current = current.next;
}
// if not found — add a new node at the beginning of the list