What Is Linked Data Structure in Java?

A linked data structure is a way of storing and organizing data in Java. It consists of a collection of nodes, where each node contains a piece of data and a reference to the next node in the sequence. This creates a linked list, where the nodes are connected through these references.

Advantages of Linked Data Structure

The linked data structure offers several advantages:

• Dynamic Size: Unlike arrays, linked lists can grow or shrink dynamically as elements are added or removed.
• Efficient Insertion and Deletion: In a linked list, adding or removing elements can be done easily by changing the references between nodes. This makes it faster than array-based structures for these operations.
• Flexibility: Linked lists allow for efficient manipulation of elements in the middle of the list. Adding or removing elements at any position does not require shifting other elements as in an array-based structure.

The Node Class

In Java, we typically represent a node in a linked list using a separate class. Here is an example:

public class Node {
    private int data;
    private Node next;

    // Constructor
    public Node(int data) {
        this.data = data;
        this.next = null;
    }

    // Getters and Setters
    public int getData() {
        return data;
    }

    public void setData(int data) {
        this.data = data;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }
}

In this example, the Node class has two instance variables: data, which stores the actual data, and next, which is a reference to the next node in the list.

The LinkedList Class

To work with linked lists, we also need a separate class to manage and manipulate the nodes. This class is commonly known as the LinkedList class. Here is an example:

public class LinkedList {
    private Node head;

    // Constructor
    public LinkedList() {
        this.head = null;
    }

    // Methods to manipulate the list
    // ..
}

The LinkedList class has a single instance variable: head, which is a reference to the first node in the list. The rest of the methods required to manipulate and traverse the list can be added to this class.

Creating a Linked List

To create a linked list, we first need to instantiate an object of the LinkedList class. Then, we can add nodes by creating instances of the Node class and linking them together using their setNext() method.

LinkedList linkedList = new LinkedList();

Node node1 = new Node(10);
Node node2 = new Node(20);
Node node3 = new Node(30);

linkedList.head = node1;
node1.setNext(node2);
node2.setNext(node3);

In this example, we create a linked list with three nodes: 10, 20, and 30. The head of the linked list is set to the first node, and each node is linked to the next one using the setNext() method.

Traversing a Linked List

To traverse a linked list and access its elements, we start from the head node and follow the next references until we reach the end of the list (i.e., when getNext() returns null). Here is an example:

Node currentNode = linkedList.head;

while(currentNode != null) {
    System.out.println(currentNode.getData());
    currentNode = currentNode.getNext();
}

In this example, we start from the head node (node1) and print its data. Then, we move to the next node by updating currentNode.

We repeat this process until we reach the end of the list (when currentNode becomes null). This allows us to traverse and access all elements in the linked list.

In Conclusion

A linked data structure provides a flexible way to store and organize data in Java. It offers advantages such as dynamic size, efficient insertion and deletion, and flexibility in manipulating elements.

By using separate classes for nodes and linked lists, we can easily create and manipulate a linked list. Traversing a linked list involves following the references between nodes from the head to the end of the list.

The use of linked data structures can greatly enhance your ability to work with complex data sets efficiently. It’s important to understand how they work and how to implement them in Java for optimal performance.