BlockingDeque addLast() method in Java with Examples

The addLast(E e) method of BlockingDeque inserts the element passed in the parameter to the end of the Deque if there is space. If the BlockingDeque is capacity restricted and no space is left for insertion, it returns an IllegalStateException.

Syntax:

public void addLast(E e)

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

Returns: This method does not returns anything.

Exception:

IllegalStateException: if the element cannot be added at this time due to capacity restrictions
NullPointerException: if the specified element is null

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

Below programs illustrate addLast() method of BlockingDeque:

Program 1:

// Java Program Demonstrate addLast() 
// 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>(); 
  
        // Add numbers to end of BlockingDeque 
        BD.addLast(7855642); 
        BD.addLast(35658786); 
        BD.addLast(5278367); 
        BD.addLast(74381793); 
  
        // before removing print Deque 
        System.out.println("Blocking Deque: " + BD); 
    } 
} 

Output:

Blocking Deque: [7855642, 35658786, 5278367, 74381793]

Program 2:

// Java Program Demonstrate addLast() 
// method of BlockingDeque 
// when it is Full 
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 
        // size of list 
        BlockingDeque<Integer> BD 
            = new LinkedBlockingDeque<Integer>(3); 
  
        // Add numbers to end of BlockingDeque 
        BD.addLast(7855642); 
        BD.addLast(35658786); 
        BD.addLast(5278367); 
  
        // it is full 
        BD.addLast(74381793); 
  
        // before removing print Deque 
        System.out.println("Blocking Deque: " + BD); 
    } 
} 

Output:

Exception in thread "main" java.lang.IllegalStateException: Deque full
    at java.util.concurrent.LinkedBlockingDeque.addLast(LinkedBlockingDeque.java:335)
    at GFG.main(GFG.java:25)

Program 3:

// Java Program Demonstrate addLast() 
// method of BlockingDeque 
// when nill is inserted 
  
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>(); 
  
        // Add numbers to end of BlockingDeque 
        BD.addLast(7855642); 
        BD.addLast(35658786); 
        BD.addLast(5278367); 
  
        // NULL 
        BD.addLast(null); 
  
        // before removing print queue 
        System.out.println("Blocking Deque: " + BD); 
    } 
} 

Output:

Exception in thread "main" java.lang.NullPointerException
    at java.util.concurrent.LinkedBlockingDeque.offerLast(LinkedBlockingDeque.java:357)
    at java.util.concurrent.LinkedBlockingDeque.addLast(LinkedBlockingDeque.java:334)
    at GFG.main(GFG.java:24)

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

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