LinkedBlockingDeque removeFirst() method in Java
The removeFirst() method of LinkedBlockingDeque returns and removes the first element of the Deque container from it. The method throws an NoSuchElementException if the Deque container is empty.
Syntax:
public E removeFirst()
Returns: This method returns the head of the Deque container, which is the first element.
Exception: The function throws a NoSuchElementException if the Deque is empty.
Below programs illustrate removeFirst() method of LinkedBlockingDeque:
Program 1:
// Java Program to demonstrate removeFirst() // method of LinkedBlockingDeque import java.util.concurrent.LinkedBlockingDeque; import java.util.*; public class GFG { public static void main(String[] args) throws InterruptedException { // create object of LinkedBlockingDeque LinkedBlockingDeque<Integer> LBD = new LinkedBlockingDeque<Integer>(); // Add numbers to end of LinkedBlockingDeque LBD.add( 7855642 ); LBD.add( 35658786 ); LBD.add( 5278367 ); LBD.add( 74381793 ); // print Dequee System.out.println( "Linked Blocking Deque: " + LBD); // removes the front element and prints it System.out.println( "First element of Linked Blocking Deque: " + LBD.removeFirst()); // prints the Deque System.out.println( "Linked Blocking Deque: " + LBD); } } |
Output:
Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793] First element of Linked Blocking Deque: 7855642 Linked Blocking Deque: [35658786, 5278367, 74381793]
Program 2:
// Java Program to demonstrate removeFirst() // method of LinkedBlockingDeque import java.util.concurrent.LinkedBlockingDeque; import java.util.*; public class GFG { public static void main(String[] args) throws NoSuchElementException { // create object of LinkedBlockingDeque LinkedBlockingDeque<Integer> LBD = new LinkedBlockingDeque<Integer>(); // print Dequee System.out.println( "Linked Blocking Deque: " + LBD); try { // throws an exception LBD.removeFirst(); } catch (Exception e) { System.out.println( "Exception when removing " + "first element from this Deque: " + e); } } } |
Output:
Linked Blocking Deque: [] Exception when removing first element from this Deque: java.util.NoSuchElementException
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