In Java, the LinkedList class is a built-in implementation of a doubly linked list data structure. A doubly linked list is a type of linked list where each node has a reference to both the next and previous nodes in the list. The LinkedList class provides methods for adding, removing, and manipulating elements in the list. Here’s an explanation of the LinkedList class in Java with examples:
Creating a LinkedList
To create a LinkedList object in Java, you can use the LinkedList class constructor. Here’s an example:
LinkedList<String> list = new LinkedList<String>();In this example, we have created a new LinkedList object that can hold String values. You can also create a LinkedList object by copying the elements of an existing collection, as shown in this example:
List<String> names = Arrays.asList("John", "Mary", "Steve");
LinkedList<String> list = new LinkedList<String>(names);In this example, we have created a new LinkedList object and initialized it with the elements of the names list.
Adding and Removing Elements
You can add elements to a LinkedList object using the add and addFirst methods. Here’s an example:
list.add("Bob");
list.addFirst("Alice");In this example, we have added the names “Bob” and “Alice” to the beginning and end of the LinkedList, respectively.
You can remove elements from a LinkedList object using the remove and removeFirst methods. Here’s an example:
list.remove("Mary");
list.removeFirst();In this example, we have removed the name “Mary” from the LinkedList and then removed the first element in the list.
Accessing Elements
You can access elements in a LinkedList object using the get method. Here’s an example:
String name = list.get(2);In this example, we have retrieved the third element in the LinkedList and stored it in a variable called name.
Iterating Over a LinkedList
You can iterate over the elements in a LinkedList object using a for loop or an iterator. Here’s an example using a for loop:
for (String name : list) {
System.out.println(name);
}In this example, we have used a for loop to iterate over the elements in the LinkedList and print them to the console.
The LinkedList class in Java provides a powerful and flexible way to store and manipulate groups of objects. By using the LinkedList class, you can write code that can adapt to changing requirements and perform complex operations on the list efficiently.