Java LinkedList clone() Method

The LinkedList.clone() method in Java is used to create a shallow copy of a LinkedList. This guide will cover the method’s usage, explain how it works, and provide examples to demonstrate its functionality.

Table of Contents

1. Introduction
2. clone Method Syntax
3. Examples
   • Cloning a LinkedList
   • Verifying Shallow Copy
4. Conclusion

Introduction

The LinkedList.clone() method is a member of the LinkedList class in Java. It allows you to create a shallow copy of the LinkedList, meaning that the new list will have the same elements as the original, but the elements themselves will not be duplicated (only their references will be copied).

clone Method Syntax

The syntax for the clone method is as follows:

public Object clone()

• The method does not take any parameters.
• The method returns an Object which should be cast to LinkedList<E>.

Examples

Cloning a LinkedList

The clone method can be used to create a shallow copy of a LinkedList.

Example

import java.util.LinkedList;

public class CloneExample {
    public static void main(String[] args) {
        // Creating a LinkedList of Strings
        LinkedList<String> list = new LinkedList<>();

        // Adding elements to the LinkedList
        list.add("Apple");
        list.add("Banana");
        list.add("Orange");

        // Cloning the LinkedList
        LinkedList<String> clonedList = (LinkedList<String>) list.clone();

        // Printing the original and cloned LinkedLists
        System.out.println("Original LinkedList: " + list);
        System.out.println("Cloned LinkedList: " + clonedList);
    }
}

Output:

Original LinkedList: [Apple, Banana, Orange]
Cloned LinkedList: [Apple, Banana, Orange]

Verifying Shallow Copy

To verify that the clone method creates a shallow copy, you can check if changes to the elements in the original list are reflected in the cloned list.

Example

import java.util.LinkedList;

public class ShallowCopyExample {
    public static void main(String[] args) {
        // Creating a LinkedList of custom objects
        LinkedList<StringBuilder> list = new LinkedList<>();

        // Adding elements to the LinkedList
        list.add(new StringBuilder("Apple"));
        list.add(new StringBuilder("Banana"));
        list.add(new StringBuilder("Orange"));

        // Cloning the LinkedList
        LinkedList<StringBuilder> clonedList = (LinkedList<StringBuilder>) list.clone();

        // Modifying an element in the original list
        list.get(0).append(" Pie");

        // Printing the original and cloned LinkedLists
        System.out.println("Original LinkedList: " + list);
        System.out.println("Cloned LinkedList: " + clonedList);
    }
}

Output:

Original LinkedList: [Apple Pie, Banana, Orange]
Cloned LinkedList: [Apple Pie, Banana, Orange]

Conclusion

The LinkedList.clone() method in Java provides a way to create a shallow copy of a LinkedList. By understanding how to use this method, you can efficiently duplicate collections of objects in your Java applications. However, it is important to note that the clone method creates a shallow copy, meaning that changes to the objects in the original list will be reflected in the cloned list since both lists hold references to the same objects.