BlockingDeque peek() method in Java with examples Last Updated : 01 Oct, 2019 Comments Improve Suggest changes Like Article Like Report 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 empty. It returns false if the container is empty. Note: The peek() method of BlockingDeque has been inherited from the LinkedBlockingDeque class in Java. Below programs illustrate peek() method of BlockingDeque: Program 1: Java // Java Program Demonstrate peek() // 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("Linked Blocking Deque: " + BD); System.out.println("Front element in Deque: " + BD.peek()); } } Output: Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793] Front element in Deque: 7855642 Program 2: Java // Java Program Demonstrate peek() // 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.peek()); } } 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#peek() Comment More infoAdvertise with us Next Article BlockingDeque peek() method in Java with examples G gopaldave Follow Improve Article Tags : Java Java-Collections Java-Functions java-interfaces Practice Tags : JavaJava-Collections Similar Reads 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 take() method in Java with Examples The take() method of BlockingDeque returns and removes the head of the Deque container from it. The method throws an InterruptedException if it is interrupted while waiting. Syntax: public E take() Returns: This method returns the head of the Deque container. Exception: The function throws a Interru 2 min read BlockingDeque poll() method in Java with examples 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 cont 2 min read BlockingDeque remove() method in Java with Examples The remove() method of BlockingDeque removes the head of the Deque container. The method throws a NoSuchElementException if the Deque container is empty. If an element in passed in the parameter, it removes the given element if present in the Deque. Syntax: public E remove() or boolean remove(elemen 2 min read BlockingDeque push() method in Java with examples The push(E e) method of BlockingDeque pushes an element onto the stack represented by this deque. It inserts the element passed in the parameter to the front of the Deque if there is space. If the BlockingDeque is capacity restricted and no space is left for insertion, it returns an IllegalStateExce 2 min read Like