Java - Deque removeLastOccurrence() Method

The Java Deque removeLastOccurrence(Object) method removes the last occurrence of the specified element in this deque. It modifies the Deque instance.

Declaration

Following is the declaration for java.util.Deque.removeLastOccurrence(o) method

public boolean removeLastOccurrence(Object o)

Parameters

o − The element whose last occurrence is to be removed from this deque, if present.

Return Value

This method returns true if the deque contains the specified element.

Exception

ClassCastException −if the class of the specified element is incompatible with this deque (optional)

NullPointerException −- if the specified element is null and this deque does not permit null elements (optional)

Example 1

The following example shows the usage of Java Deque removeLastOccurrence() method with Integers. We're creating an Deque of Integers, adding some elements, print it and then use removeLastOccurrence() method to remove last occurence of an element. As Deque is modified it is printed to check if last occurence of that element is removed or not.

package com.tutorialspoint;

import java.util.ArrayDeque;
import java.util.Deque;

public class DequeDemo {
   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(25);
      deque.add(30);
      deque.add(20);
      deque.add(18);  
      deque.add(20);      

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

      // it will remove last occurrence of element
      System.out.println("Element removed : " + deque.removeLastOccurrence(20));
	  
      // let us print all the elements available in deque again
      System.out.println("Deque = " + deque);
   }
}

Output

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

Deque = [25, 30, 20, 18, 20]
Element removed : true
Deque = [25, 30, 20, 18]

Example 2

The following example shows the usage of Java Deque removeLastOccurrence() method with Strings. We're creating an Deque of Strings, adding some elements, print it and then use removeLastOccurrence() method to remove last occurence of an element. As Deque is modified it is printed to check if last occurence of that element is removed or not.

package com.tutorialspoint;

import java.util.ArrayDeque;
import java.util.Deque;

public class DequeDemo {
   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("C");	  

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

      // it will remove last occurrence of element
      System.out.println("Element removed : " + deque.removeLastOccurrence("C"));
	  
      // let us print all the elements available in deque again
      System.out.println("Deque = " + deque);
   }
}

Output

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

Deque = [A, B, C, D, C]
Element removed : true
Deque = [A, B, C, D]

Example 3

The following example shows the usage of Java Deque removeLastOccurrence() method with Student objects. We're creating an Deque of Student objects, adding some elements, print it and then use removeLastOccurrence() method to remove last occurence of an element. As Deque is modified it is printed to check if last occurence of that element is removed or not.

package com.tutorialspoint;

import java.util.ArrayDeque;
import java.util.Deque;

public class DequeDemo {
   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"));       
      deque.add(new Student(2, "Robert"));
	  
      // let us print all the elements available in deque
      System.out.println("Deque = " + deque);

      // it will remove last occurrence of element
      System.out.println("Element removed : " + deque.removeLastOccurrence(new Student(2, "Robert")));
	  
      // let us print all the elements available in deque again
      System.out.println("Deque = " + 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 + " ]";
   }
   
   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
}

Output

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

Deque = [[ 1, Julie ], [ 2, Robert ], [ 3, Adam ], [ 2, Robert ]]
Element removed : true
Deque = [[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]