BlockingDeque poll() method in Java with examples Last Updated : 01 Oct, 2019 Comments Improve Suggest changes Like Article Like Report The poll() method of BlockingDeque returns the front element in the Deque container and deletes it. It returns null if the container is empty. Syntax: public E poll() Parameters: This method does not accept any parameters. Returns: This method returns front element of the Deque container if the container is not empty and deletes it. It returns null if the container is empty. Note: The poll() method of BlockingDeque has been inherited from the LinkedBlockingDeque class in Java. Below programs illustrate poll() method of BlockingDeque: Program 1: Java // Java Program Demonstrate poll() // method of BlockingDeque import java.util.concurrent.LinkedBlockingDeque; import java.util.concurrent.BlockingDeque import java.util.*; public class GFG { public static void main(String[] args) { // create object of BlockingDeque BlockingDeque<Integer> BD = new LinkedBlockingDeque<Integer>(); // Add numbers to end of BlockingDeque BD.add(7855642); BD.add(35658786); BD.add(5278367); BD.add(74381793); // Print the queue System.out.println("Blocking Deque: " + BD); System.out.println("Front element in Deque: " + BD.poll()); // One element is deleted as poll was called System.out.println("Blocking Deque: " + BD); } } Output: Blocking Deque: [7855642, 35658786, 5278367, 74381793] Front element in Deque: 7855642 Blocking Deque: [35658786, 5278367, 74381793] Program 2: Java // Java Program Demonstrate poll() // method of BlockingDeque // when Deque is empty import java.util.concurrent.LinkedBlockingDeque; import java.util.concurrent.BlockingDeque import java.util.*; public class GFG { public static void main(String[] args) { // create object of BlockingDeque BlockingDeque<Integer> BD = new LinkedBlockingDeque<Integer>(); // Add numbers to end of BlockingDeque BD.add(7855642); BD.add(35658786); BD.add(5278367); BD.add(74381793); // Print the queue System.out.println("Blocking Deque: " + BD); // empty deque BD.clear(); System.out.println("Front element in Deque: " + BD.poll()); } } Output: Blocking Deque: [7855642, 35658786, 5278367, 74381793] Front element in Deque: null Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#poll(long, %20java.util.concurrent.TimeUnit) Comment More infoAdvertise with us Next Article BlockingDeque poll() method in Java with examples G gopaldave Follow Improve Article Tags : Java Java-Collections Java-Functions java-interfaces Practice Tags : JavaJava-Collections Similar Reads BlockingQueue poll() method in Java with examples The poll(long timeout, TimeUnit unit) method of BlockingQueue interface returns the head of BlockingQueue by removing that element from the queue. It can be said that this method retrieves and removes element from head of this LinkedBlockingQueue. If queue is empty, then poll() method will wait till 3 min read BlockingDeque pollLast() method in Java with examples The pollLast() method of BlockingDeque returns the last element in the Deque container, and deletes it. It returns null if the container is empty. Syntax: public E pollLast() Parameters: This method does not accept any parameters. Returns: This method returns last element in the Deque container if t 2 min read BlockingDeque pollFirst() method in Java with examples The pollFirst() method of BlockingDeque returns the front element in the Deque container, and deletes it. It returns null if the container is empty. Syntax: public E pollFirst() Parameters: This method does not accept any parameters. Returns: This method returns front element in the Deque container 2 min read BlockingDeque put() method in Java with Examples The put(E e) method of BlockingDeque inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque). If the Deque is capacity restricted, then it will wait for the space to become available. Syntax: public void put(E e) Parameters: This method acce 2 min read BlockingDeque peek() method in Java with examples The peek() method of BlockingDeque returns the front element in the Deque container. It returns null if the container is empty. Syntax: public E peek() Parameters: This method does not accept any parameters. Returns: This method returns front element in the Deque container if the container is not em 2 min read Like