ConcurrentLinkedDeque removeFirstOccurrence() method in Java
Last Updated :
15 Nov, 2022
The java.util.concurrent.ConcurrentLinkedDeque.removeFirstOccurrence() method is an in-built method in Java which accepts a parameter and removes the first appearance of that element in the deque. Thus, in case the element is not present in the deque, it remains unchanged. Syntax:
public boolean removeFirstOccurrence(Object o)
Parameters: The function accepts an object elem as parameter which denotes the object whose first appearance from the deque is to be removed. Return Value: The function returns true if elem is present in the deque and returns false otherwise. Exception: The function throws NullPointerException if the specified element passed as parameter to the function is null. Below programs illustrate the use of removeFirstOccurrence() method : Program 1:
Java
import java.util.concurrent.*;
class ConcurrentLinkedDequeDemo {
public static void main(String[] args)
{
ConcurrentLinkedDeque<String> cld = new ConcurrentLinkedDeque<String>();
cld.addFirst("GFG");
cld.addFirst("Geeks");
cld.addFirst("Gfg");
cld.addFirst("gfg");
cld.addFirst("Geeks");
System.out.println("Elements in "
+ "the LinkedDeque: " + cld);
cld.removeFirstOccurrence("Geeks");
System.out.println("Elements in "
+ "the LinkedDeque: " + cld);
}
}
|
Output:
Elements in the LinkedDeque: [Geeks, gfg, Gfg, Geeks, GFG]
Elements in the LinkedDeque: [gfg, Gfg, Geeks, GFG]
Program 2:
Java
import java.util.concurrent.*;
class ConcurrentLinkedDequeDemo {
public static void main(String[] args)
{
ConcurrentLinkedDeque<Integer> cld = new ConcurrentLinkedDeque<Integer>();
cld.addFirst( 12 );
cld.addFirst( 280 );
cld.addFirst( 1008 );
cld.addFirst( 1050 );
cld.addFirst( 379 );
System.out.println("Elements in "
+ "the LinkedDeque: " + cld);
try {
cld.removeFirstOccurrence( null );
}
catch (Exception e) {
System.out.println(e);
}
}
}
|
Output:
Elements in the LinkedDeque: [379, 1050, 1008, 280, 12]
java.lang.NullPointerException
Reference:https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html#removeFirstOccurrence()
Share your thoughts in the comments
Please Login to comment...