LinkedBlockingDeque pop() method in Java
Last Updated :
14 Sep, 2018
The pop() method of LinkedBlockingDeque pops an element from the stack represented by this deque. In other words, it removes and returns the first element of this deque. It returns null if the container is empty.
Syntax:
public E pop()
Parameters: This method does not accept any parameters.
Returns: This method returns the element at the front of this deque (which is the top of the stack represented by this deque). It throws an NoSuchElementException if the deque is empty.
Below programs illustrate pop() method of LinkedBlockingDeque:
Program 1:
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
throws NoSuchElementException
{
LinkedBlockingDeque<Integer> LBD
= new LinkedBlockingDeque<Integer>();
LBD.addFirst( 7855642 );
LBD.addFirst( 35658786 );
LBD.addFirst( 5278367 );
LBD.addFirst( 74381793 );
System.out.println( "Linked Blocking Deque: " + LBD);
System.out.println( "Front element in Deque: " + LBD.pop());
System.out.println( "Linked Blocking Deque: " + LBD);
}
}
|
Output:
Linked Blocking Deque: [74381793, 5278367, 35658786, 7855642]
Front element in Deque: 74381793
Linked Blocking Deque: [5278367, 35658786, 7855642]
Program 2:
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
LinkedBlockingDeque<Integer> LBD
= new LinkedBlockingDeque<Integer>();
LBD.add( 7855642 );
LBD.add( 35658786 );
LBD.add( 5278367 );
LBD.add( 74381793 );
LBD.clear();
System.out.println( "Front element in Deque: " + LBD.pop());
}
}
|
Output:
Exception in thread "main" java.util.NoSuchElementException
at java.util.concurrent.LinkedBlockingDeque.removeFirst(LinkedBlockingDeque.java:453)
at java.util.concurrent.LinkedBlockingDeque.pop(LinkedBlockingDeque.java:777)
at GFG.main(GFG.java:27)
Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedBlockingDeque.html#pop()
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