Difference Between a Static Queue and a Singly Linked List in Java

In Java List and Queue both are introduced as an ordered list of objects, where the same object may be added more than once. The difference between both comes in the manner of adding elements. In the queue, all the elements get inserted at the rear and removed from the front while we can add an element anywhere in the list.

Example of Static queue and Singly Linked List.

StaticQueueDemo.java

 Live Demo

import java.util.*;
public class StaticQueueDemo {
   public static void main(String args[]) {
      PriorityQueue < String > queue = new PriorityQueue < String > ();
      queue.add("Jack");
      queue.add("Smith");
      queue.add("John");
      System.out.println("head:" + queue.element());
      System.out.println("head:" + queue.peek());
      System.out.println("iterating the queue elements:");
      Iterator itr = queue.iterator();
      while (itr.hasNext()) {
         System.out.println(itr.next());
      }
      queue.remove();
      queue.poll();
      System.out.println("after removing two elements:");
      Iterator < String > itr2 = queue.iterator();
      while (itr2.hasNext()) {
         System.out.println(itr2.next());
      }
   }
}

Output

head:Jack
head:Jack
iterating the queue elements:
Jack
Smith
John
after removing two elements:
Smith

Example

LinkedListDemo.java

 Live Demo

import java.util.*;
public class LinkedListDemo {
   public static void main(String[] args) {
      // Creating a LinkedList
      LinkedList < String > friends = new LinkedList <> ();
      // Adding new elements to the end of the LinkedList using add() method.
      friends.add("John");
      friends.add("Jack");
      friends.add("Smith");
      friends.add("Chris");
      System.out.println("Initial LinkedList : " + friends);
      // Adding an element at the specified position in the LinkedList
      friends.add(3, "Lisa");
      System.out.println("After add(3, \"Lisa\") : " + friends);
   }
}

Output

Initial LinkedList : [John, Jack, Smith, Chris]
After add(3,"Lisa") : [John, Jack, Smith, Chris, Lisa]