A sample implementation of a Linked List with basic operations in Java

LinkedList.java

/**
 *
 * @author Mahdhi
 */

public class LinkedList{
    Node head;  // head of list
    public LinkedList(){
        head=null;
    }
    
    public boolean isEmpty(){
        return head==null;
    }
    
    public void insertAtBeginning(int new_data) {
    // insert the data
    Node new_node = new Node(new_data);
    new_node.next = head;
    head = new_node;
  }
    
    public void insertAtEnd(int new_data) {
    Node new_node = new Node(new_data);

    if (head == null) {
      head = new Node(new_data);
      return;
    }

    new_node.next = null;

    Node last = head;
    while (last.next != null)
      last = last.next;

    last.next = new_node;
    return;
  }
    
    public void insertAfter(Node prev_node, int new_data) {
    if (prev_node == null) {
      System.out.println("The given previous node cannot be null");
      return;
    }
    Node new_node = new Node(new_data);
    new_node.next = prev_node.next;
    prev_node.next = new_node;
  }
    
    public Node search(int key){
       Node temp = head;
       while(temp != null){
           if(temp.key == key){
               return temp;
           }
           temp = temp.next;
       }
       return null;
    }
}