In this article, you will know how to add item to the linked list java. If you are using the LinkedList type taken from the Java collections, you have several options:
- Adding the element at the beginning of the Linked List
linkedList.addFirst(1);

2. Adding the element at the end of the Linked List
linkedList.addLast(15);

3. Adding the element in needed place by index
linkedList.add(3, 45);
// On item with index 3 we will put value 45

How to add items to the linked list in java without collections?
If you have implemented the Linked List by yourself. I have explained it in this article. Or you want to know in details how it works because it is one of the questions on the interview; here are some examples:
- Adding the element before the first element (Picture will be the same as number 1 from the previous example)
private void putValueInTheBeginningOfTheLinkedList() {
//You need to create linked list first
creatingLinkedList();
//Creating new node
ListNode newNode = new ListNode(999);
//Connecting it on the left side of the head of the linked list. Before the first element
newNode.next = head;
//Moving head to the beginning of the list
head = newNode;
//Going back to the start to go through the list for logging
ListNode selectedItem = head;
//Going through the list until last item don't have connection
while (selectedItem != null) {
Log.d("linkedList", "-> " + selectedItem.data);
selectedItem = selectedItem.next;
}
}
2. Adding the element after the last element. (Picture will be the same as number 1 from the previous example)
private void putValutInTheEndOfTheLinkedList() {
//You need to create linked list first
creatingLinkedList();
//Creating item to put it in the list
ListNode newNode = new ListNode(999);
//Finding the first item from the list
ListNode selectedItem = head;
//Moving selected item to the right until last item don't have a connection
while (selectedItem.next != null) {
selectedItem = selectedItem.next;
}
//We are on the last item. Connecting it to the new item
selectedItem.next = newNode;
//Going back to the start to go through the list for logging
selectedItem = head;
//Going through the list until last item don't have connection
while (selectedItem != null) {
Log.d("linkedList", "-> " + selectedItem.data);
selectedItem = selectedItem.next;
}
}
In this article, you figured out how to add item to the linked list java in two ways. With the help of the Java collections and in case of implementation via constructor and model class.
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