Wednesday, July 8, 2026
HomeLanguagesJavaBlockingDeque offerFirst() method in Java with Examples

BlockingDeque offerFirst() method in Java with Examples

The offerFirst(E e) method of BlockingDeque inserts the element passed in the parameter at the front of the Deque container. If the container’s capacity has exceeded, then it does not returns an exception as in case of add() and addFirst() function.

Syntax: 

public boolean offerFirst(E e)

Parameters: This method accepts a mandatory parameter e which is the element to be inserted at the front of the BlockingDeque. 

Returns: This method returns true if the element has been inserted, else it returns false. 

Note: The offerFirst() method of BlockingDeque has been inherited from the LinkedBlockingDeque class in Java. 

Below programs illustrate offerFirst() method of LinkedBlockingDeque:

Program 1:  

Java




// Java Program Demonstrate offerFirst()
// method of BlockingDeque
 
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
 
        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>(4);
 
        // Add numbers to end of BlockingDeque
        BD.offerFirst(7855642);
        BD.offerFirst(35658786);
        BD.offerFirst(5278367);
        BD.offerFirst(74381793);
 
        // Cannot be inserted
        BD.offerFirst(10);
 
        // cannot be inserted hence returns false
        if (!BD.offerFirst(10))
            System.out.println("The element 10 cannot be inserted"
                               + " as capacity is full");
 
        // before removing print queue
        System.out.println("Blocking Deque: " + BD);
    }
}


Output: 

The element 10 cannot be inserted as capacity is full
Blocking Deque: [74381793, 5278367, 35658786, 7855642]

 

Program 2: 

Java




// Java Program Demonstrate offerFirst()
// method of BlockingDeque
 
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
 
        // create object of BlockingDeque
        BlockingDeque<String> BD
            = new LinkedBlockingDeque<String>(4);
 
        // Add numbers to end of BlockingDeque
        BD.offerFirst("abc");
        BD.offerFirst("gopu");
        BD.offerFirst("geeks");
        BD.offerFirst("richik");
 
        // Cannot be inserted
        BD.offerFirst("hii");
 
        // cannot be inserted hence returns false
        if (!BD.offerFirst("hii"))
            System.out.println("The element 'hii' cannot be"
                               + " inserted as capacity is full");
 
        // before removing print queue
        System.out.println("Blocking Deque: " + BD);
    }
}


Output: 

The element 'hii' cannot be inserted as capacity is full
Blocking Deque: [richik, geeks, gopu, abc]

 

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#offerFirst(E)
 

RELATED ARTICLES

4 COMMENTS

Most Popular

Dominic
32519 POSTS0 COMMENTS
Milvus
131 POSTS0 COMMENTS
Nango Kala
6900 POSTS0 COMMENTS
Nicole Veronica
12016 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12111 POSTS0 COMMENTS
Shaida Kate Naidoo
7019 POSTS0 COMMENTS
Ted Musemwa
7263 POSTS0 COMMENTS
Thapelo Manthata
6978 POSTS0 COMMENTS
Umr Jansen
6968 POSTS0 COMMENTS