The removeFirstOccurrence() method is used to remove the first occurrence of the specified element in the ConcurrentLinkedDeque object.
ConcurrentLinkedDequeis a thread-safe unbounded deque. Thenullvalue is not permitted as an element. We can useConcurrentLinkedDequewhen multiple threads are sharing a single Deque.
public boolean removeFirstOccurrence(Object o)
This method takes the element to be removed from the deque as a parameter.
This method returns true if the deque contains the specified element. Otherwise, false is returned.
The code below demonstrates how to use the removeFirstOccurrence() method.
import java.util.concurrent.ConcurrentLinkedDeque;class RemoveFirstOccurrence {public static void main( String args[] ) {ConcurrentLinkedDeque<String> deque = new ConcurrentLinkedDeque<>();deque.add("1");deque.add("2");deque.add("1");System.out.println("The deque is " + deque);System.out.println("Is element 1 present & removed: " + deque.removeFirstOccurrence("1"));System.out.println("The deque is " + deque);System.out.println("Is element 4 present & removed: " + deque.removeFirstOccurrence("1"));System.out.println("The deque is " + deque);}}
In the code above:
Line 1: We imported the ConcurrentLinkedDeque class.
Line 4: We created a ConcurrentLinkedDeque object with the name deque.
Lines 6 to 8: We used the add() method of the deque object to add three elements, ("1","2","3"), to deque.
Line 11: We used the removeFirstOccurrence() method to remove the first occurrence of the element "1".
The element "1" is present in two indexes, 0 and 2. After calling this method, the element at index 0 will be removed.
Line 15: We used the removeFirstOccurrence() method to remove the first occurrence of the element "4".
The element "4" is not present. Therefore, this method returns false.