The java.util.ArrayDeque.pollFirst() method in Java is used to retrieve or fetch and remove the first element of the Deque. The peekFirst() method only retrieved the first element but the pollFirst() also removes the element along with the retrieval. It returns NULL if the deque is empty.
Syntax:
Array_Deque.pollFirst()
Parameters: The method does not take any parameter.
Return Value: The method removes the first element of the Deque and returns the same. It returns NULL if the deque is empty.
Below programs illustrate the Java.util.ArrayDeque.pollFirst() method:
Program 1:
Output:
ArrayDeque: [Welcome, To, Geeks, 4, Geeks]
The element at head is: Welcome
ArrayDeque after operation: [To, Geeks, 4, Geeks]
Program 2:
Output:
ArrayDeque: [10, 15, 30, 20, 5]
The element at head is: 10
ArrayDeque after operation: [15, 30, 20, 5]
Program 3: For an empty deque:
