Java ArrayDeque addLast() Method



Description

The Java ArrayDeque addLast(E e) method inserts the specified element E at the end of the deque. It maintains the insertion order. When we calls this method multiple times, elements keeps appending to the list in the end of it.

Declaration

Following is the declaration for java.util.ArrayDeque.addLast() method

public void addLast(E e)

Parameters

e − The element to be added at the end.

Return Value

This method does not return any value.

Exception

NullPointerException − if the specified element is null.

Example 1

The following example shows the usage of Java ArrayDeque addLast(E) method with Integers. We're adding few elements to list using add() method and then using addLast() method, we're adding two elements in the end. Lastly we're printing the ArrayDeque object to see the final result.

package com.tutorialspoint;
import java.util.ArrayDeque;
import java.util.Deque;
public class ArrayDequeDemo {
   public static void main(String[] args) {

      // create an empty array deque
      Deque<Integer> deque = new ArrayDeque<>();

      // use add() method to add elements in the deque
      deque.add(1);
      deque.add(2);
      deque.add(3);
      deque.add(4);        
      deque.add(5);
      deque.add(6);

      // the values will be printed in the same order
      deque.addLast(7);
      deque.addLast(8);

      // let us print all the elements available in deque
      System.out.println("ArrayDeque = " + deque);      
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayDeque = [1, 2, 3, 4, 5, 6, 7, 8]

Example 2

The following example shows the usage of Java ArrayDeque addLast(E) method with Strings. We're adding few elements to list using add() method and then using addLast() method, we're adding two elements in the end. Lastly we're printing the ArrayDeque object to see the final result.

package com.tutorialspoint;
import java.util.ArrayDeque;
import java.util.Deque;
public class ArrayDequeDemo {
   public static void main(String[] args) {

      // create an empty array deque
      Deque<String> deque = new ArrayDeque<>();

      // use add() method to add elements in the deque
      deque.add("A");
      deque.add("B");
      deque.add("C");
      deque.add("D");        
      deque.add("E");
      deque.add("F");

      // the values will be printed in the same order
      deque.addLast("G");
      deque.addLast("H");

      // let us print all the elements available in deque
      System.out.println("ArrayDeque = " + deque);      
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayDeque = [A, B, C, D, E, F, G, H]

Example 3

The following example shows the usage of Java ArrayDeque addLast(E) method with Student objects. We're adding few elements to list using add() method and then using addLast() method, we're adding two elements in the end. Lastly we're printing the ArrayDeque object to see the final result.

package com.tutorialspoint;
import java.util.ArrayDeque;
import java.util.Deque;
public class ArrayDequeDemo {
   public static void main(String[] args) {

      // create an empty array deque
      Deque<Student> deque = new ArrayDeque<>();

      // use add() method to add elements in the deque
      deque.add(new Student(1, "Julie"));
      deque.add(new Student(2, "Robert"));
      deque.add(new Student(3, "Adam"));

      // use addLast() method to add element at the end of the deque
      deque.addLast(new Student(4, "Rohan"));
      deque.addLast(new Student(5, "Sohan"));

      // let us print all the elements available in deque
      System.out.println("ArrayDeque = " + deque);      
   }
}
class Student {
   int rollNo;
   String name;
   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayDeque = [[ 1, Julie ], [ 2, Robert ], [ 3, Adam ], [ 4, Rohan ], [ 5, Sohan ]]
java_util_arraydeque.htm
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