how to instantiate a queue in java
A Queue is an interface, which means you cannot construct a Queue directly.
Queue<Integer> q = new LinkedList<Integer>();
or
Queue<Integer> q = new ArrayDeque<Integer>();
You can’t instantiate an interface directly except via an anonymous inner class.
import java.util.*; public class Main { public static void main(String[] args) { Queue queue = new LinkedList(); queue.add(44); queue.add(45); queue.add(46); // remove () =>removes first element from the queue queue.remove(); // 44 removed // element() => returns head of the queue queue.element(); // 45 // peek() => returns the head of the queue without removing it. queue.peek(); // 45 } }