See the documentation for ArrayList#remove(int), as in the following syntax:
list.remove(list.size() - 1)
Here is how it's implemented. elementData does a lookup on the backing array (so it can cut it loose from the array), which should be constant time (since the JVM knows the size of an object reference and the number of entries it can calculate the offset), and numMoved is 0 for this case:
public E remove(int index) {
rangeCheck(index); // throws an exception if out of bounds
modCount++; // each time a structural change happens
// used for ConcurrentModificationExceptions
E oldValue = elementData(index);
int numMoved = size - index - 1;
if (numMoved > 0)
System.arraycopy(elementData, index+1, elementData, index,
numMoved);
elementData[--size] = null; // Let gc do its work
return oldValue;
}
Top answer 1 of 2
97
See the documentation for ArrayList#remove(int), as in the following syntax:
list.remove(list.size() - 1)
Here is how it's implemented. elementData does a lookup on the backing array (so it can cut it loose from the array), which should be constant time (since the JVM knows the size of an object reference and the number of entries it can calculate the offset), and numMoved is 0 for this case:
public E remove(int index) {
rangeCheck(index); // throws an exception if out of bounds
modCount++; // each time a structural change happens
// used for ConcurrentModificationExceptions
E oldValue = elementData(index);
int numMoved = size - index - 1;
if (numMoved > 0)
System.arraycopy(elementData, index+1, elementData, index,
numMoved);
elementData[--size] = null; // Let gc do its work
return oldValue;
}
2 of 2
10
Since Java 21, simply using List.removeLast, for example:
List<Integer> list = new ArrayList<>(List.of(1, 2, 3));
System.out.println(list.removeLast()); // 3 - removes and returns the last element
Note: if the list is not empty, the implementation of List.removeLast returns the result of calling remove(size() - 1). Otherwise, it throws NoSuchElementException.
The time complexity of removing the last element from ArrayList is O(1) - it is just decrementing the size of the list by 1 under the hood.
GeeksforGeeks
geeksforgeeks.org › java › removing-last-element-from-arraylist-in-java
Removing last element from ArrayList in Java - GeeksforGeeks
July 12, 2025 - ArrayList provides two overloaded remove() method: remove(int index) : Accept index of the object to be removed. We can pass the last elements index to the remove() method to delete the last element.
Is there an easy and elegant way of removing the last element of an array?
Select-Object -SkipLast should work. Can you demonstrate the issue you are seeing with hashtables? If I run @{}.GetType() the reported type is System.Collections.Hashtable. And if I run: $Array = @{}, @{}, @{} | select -SkipLast 1 $Array[0].GetType() I still get the expected: System.Collections.Hashtable type. Anyway, if you for whatever reason don't want to use Select-Object the cleanest I can think of would be this: $MyArray = @(Get-ChildItem C:\) if ($MyArray.Count -gt 0) { [array]::Resize([ref] $MyArray, $MyArray.Count - 1) } Do keep in mind though that this only works if it's an actual array, hence the need to wrap it in @() so that even if it returns 1 item I still get an array. More on reddit.com
38
20
January 14, 2025java - Removing the last element of an ArrayList - Stack Overflow
I'm new to Java and I'm stuck with an exercise I've been trying to solve for over a week now and I don't know what I'm doing wrong. I need to delete the last elements of an ArrayList, an integer in this case. The problem is that when I run the test, it still returns the old values. Copypublic static void removeLastOccurrence... More on stackoverflow.com
How does an ArrayList remove an element from an array?
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March 15, 2023Why is it that removing an element from the start of an array O(n) while at the end O(1)?
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8
2
September 16, 2023Videos
#112 Java Remove ArrayList Element
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Remove elements from an arraylist in Java - YouTube
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W3Schools
w3schools.com › java › ref_arraylist_remove.asp
Java ArrayList remove() Method
If a value is specified and multiple elements in the list have the same value then only the first one is deleted. If the list contains integers and you want to delete an integer based on its value you will need to pass an Integer object. See More Examples below for an example. ... T refers to the data type of items in the list. Remove an integer from the list by position and by value: import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<Integer> list = new ArrayList<Integer>(); list.add(5); list.add(8); list.add(9); list.add(1); list.remove(Integer.valueOf(1)); // Remove by object list.remove(1); // Remove by index System.out.println(list); } }
Oracle
docs.oracle.com › en › java › javase › 21 › docs › api › java.base › java › util › ArrayList.html
ArrayList (Java SE 21 & JDK 21)
January 20, 2026 - Removes from this list all of its elements that are contained in the specified collection. ... Removes and returns the first element of this collection (optional operation). ... Removes all of the elements of this collection that satisfy the given predicate. ... Removes and returns the last element of this collection (optional operation).
Reddit
reddit.com › r/powershell › is there an easy and elegant way of removing the last element of an array?
r/PowerShell on Reddit: Is there an easy and elegant way of removing the last element of an array?
January 14, 2025 -
Edit: Solved
It's much more flexible to use generic lists instead of arrays. Arrays are immutable and should not be used when there is a need to add or remove elements. Another option is to use array lists, but others reported that they are deprecated and that generic lists should be used instead.
Thank you all for the help!
-------------
PowerShell 7, an array like $array = @()
Like the title say - is there?
The solutions I've found online are all wrong.
- Array slicing
$array = $array[0..($array.Length - 2)]
This does not work if the array length is 1, because it resolves to $array[0..-1]. Step-by-step debugging shows that instead of deleting the last remaining element of the array, it will duplicate that element. The result will be an array of 2 elements, not 0.
- Select-Object
$array = $array | Select-Object -SkipLast 1
This does not work well with Hashtables as array elements. If your array elements are Hashtables, it will convert them to System.Collections.Hashtable. Hashtable ($example = @{}) and System.Collection.Hashtable are not the same type and operations on those two types are different (with different results).
Edit for the above: There was a typo in that part of my code and it returned some nonsense results. My bad.
- System.Collections.ArrayList
Yes, you can convert an array to System.Collection.ArrayList, but you are then working with System.Collections.ArrayList, not with an array ($array = @()).
----------------
One solution to all of this is to ask if the array length is greater than one, and handle arrays of 1 and 0 elements separately. It's using an if statement to simply remove the last element of an array, which is really bad.
Another solution is to loop through an array manually and create a new one while excluding the last element.
And the last solution that I've found is not to use arrays at all and use generic lists or array lists instead.
Is one of these options really the only solution or is there something that I'm missing?
Top answer 1 of 7
19
Arraylist has been deprecated for a good long while now. Use a [system.collections,generic.list[]] instead. They can be strongly typed and provide a mechanism to control integrity and better error handling when doing so. Plus they don’t have output when you manipulate them unlike an arraylist.
2 of 7
6
Select-Object -SkipLast should work. Can you demonstrate the issue you are seeing with hashtables? If I run @{}.GetType() the reported type is System.Collections.Hashtable. And if I run: $Array = @{}, @{}, @{} | select -SkipLast 1 $Array[0].GetType() I still get the expected: System.Collections.Hashtable type. Anyway, if you for whatever reason don't want to use Select-Object the cleanest I can think of would be this: $MyArray = @(Get-ChildItem C:\) if ($MyArray.Count -gt 0) { [array]::Resize([ref] $MyArray, $MyArray.Count - 1) } Do keep in mind though that this only works if it's an actual array, hence the need to wrap it in @() so that even if it returns 1 item I still get an array.
Baeldung
baeldung.com › home › java › java list › removing an element from an arraylist
Removing an Element From an ArrayList | Baeldung
April 4, 2025 - As we can see, removeLast() is pretty straightforward to use and easier to understand. Therefore, if we’re using JDK 21 or higher, this method can be a good option for removing the last element from a List. Sometimes, we want to remove an element from an ArrayList while we’re looping it.
CodeGym
codegym.cc › java blog › java collections › how to remove an element from arraylist in java?
How to remove an element from ArrayList in Java | CodeGym
December 10, 2024 - The iterator is smarter than it may appear: remove() removes the last element returned by the iterator. As you can see, it did just what we wanted it to do :) In principle, this is everything you need to know about removing elements from an ...
Xenovation
xenovation.com › home › blog › java › how to remove the last element from list in java?
How to remove the last element from List in Java? (ArrayList, LinkedList, Vector)
June 24, 2020 - The fastest way is to use the remove(pList.size()-1) of the List interface to remove the last entry. import java.util.ArrayList; import java.util.List; public class RemoveLastElementFromList { public static void main(String[] args) { List lList ...
Quora
quora.com › How-do-you-remove-the-first-and-last-elements-from-a-Java-List
How to remove the first and last elements from a Java List - Quora
Answer (1 of 2): You’re not specifying the list type to be used. The most efficient way to remove the head and tail nodes of a list depends on the concrete list. The general solution (ignoring bound checks for now) is to do the following: [code]List list = ...; list.remove(0); list.remov...
Tutorjoes
tutorjoes.in › Java_example_programs › remove_the_given_element_from_an_arraylist_in_java
Write a Java program to Remove the given element from an ArrayList
import java.util.ArrayList; public class Remove_GivenElement { public static void main(String[] args) { ArrayList<String> fru_list = new ArrayList<String>(); fru_list.add("Pineapple"); fru_list.add("Papaya"); fru_list.add("Mulberry"); fru_list.add("Apple"); fru_list.add("Banana"); fru_list.add("Cherry"); fru_list.add("Guava"); fru_list.add("Watermelon"); System.out.println("Given ArrayList : "+fru_list); //Removing first occurrence of "Mulberry" fru_list.remove("Mulberry"); //Removing first occurrence of "Guava" fru_list.remove("Guava"); System.out.println("\nRemove the given Element from an ArrayList.."); System.out.println(fru_list); } }
Naukri
naukri.com › code360 › library › remove-an-element-from-an-array-in-java
Remove an Element from Array in Java with Example
Almost there... just a few more seconds
Tutorialride
tutorialride.com › java-collection-framework-programs › add-retrieve-and-remove-element-from-arraylist.htm
Add, retrieve and remove element from ArrayList
import java.util.*; class ArrayListDemo { public static void main(String[] args) { ArrayList<String> al = new ArrayList<String>(); System.out.println("Size of ArrayList: "+al.size()); //Adding the elements al.add("Java"); al.add("JDBC"); System.out.println("Elements of first ArrayList: "+al); ArrayList<String> al2 = new ArrayList<String>(); al2.add("EJB"); al2.add("Struts"); //Adding the both array al2.addAll(al); System.out.println("Elements of second ArrayList: "+al2); //remove the element al2.remove("EJB"); System.out.println("Elements of ArrayList after deletion: "+al2); System.out.println("Size of ArrayList: "+al2.size()); //Retriving 2nd index element System.out.println("The element at 2nd index is: "+al2.get(2)); } } Output:
PREP INSTA
prepinsta.com › home › java tutorial › java arraylist remove() method
Java ArrayList remove() Method | PrepInsta
December 13, 2022 - If index is passed as parameter , it removes the element from the specified position If object is passed as parameter , it removes the first occurrence of the object and returns true if object is present in the list. ... When index is passed as parameter. ... package com.company; import java.util.ArrayList; // Main class public class prepInsta { // Main driver method public static void main (String[]args) { //Creating an Integer ArrayList List < Integer > list = new ArrayList <> (); // adding elements in the list list.add (1); list.add (2); list.add (3); list.add (11); list.add (21); // calling remove() method using index list.remove (1); list.remove (1); // Printing the updated ArrayList System.out.println (list); } }
Sarthaks eConnect
sarthaks.com › 3493086 › how-to-remove-elements-from-a-java-linkedlist
How to remove elements from a Java LinkedList? - Sarthaks eConnect | Largest Online Education Community
April 25, 2023 - LIVE Course for free · You can remove elements from a Java LinkedList using several different methods. Here are some of the most commonly used methods:
Tutorjoes
tutorjoes.in › Java_example_programs › retrieve_and_remove_the_tail_last_item_in_java
Write a Java program to Retrieve and Remove the tail/last item from the LinkedList
import java.util.LinkedList; public class Retrieve_Remove { public static void main(String[] args) { LinkedList list = new LinkedList(); list.add(18); list.add("JAVA"); list.add(54.78); list.add('J'); list.add(true); System.out.println("LinkedList Items : " + list); System.out.println("Tail Item : " + list.pollLast()); System.out.println("LinkedList Items : " + list); System.out.println("Tail Item : " + list.pollLast()); System.out.println("LinkedList Items : " + list); } }
IIT Kanpur
iitk.ac.in › esc101 › 05Aug › tutorial › collections › implementations › list.html
List Implementations
Think of ArrayList as Vector without the synchronization overhead. If you frequently add elements to the beginning of the List or iterate over the List to delete elements from its interior, you should consider using LinkedList. These operations require constant time in a LinkedList and linear time in an ArrayList.
Talkerscode
talkerscode.com › howto › how-to-remove-an-element-from-an-array-java.php
How To Remove An Element From An Array Java
As a result, we will remove all ArrayList elements whose names begin with the letter 'b' using the removeIf() method.
Kuros
kuros.in › java › collection-list-arraylist-linked-list
List, ArrayList, LinkedList - Kuros.in
January 17, 2019 - [A, B, C, D] [1, A, B, C, D, 2] The first value = 1 The last value = 2 The value removed from the first position of list = 1 The value removed from the last position of list = 2 [A, B, C, D] Similar to the ArrayList, we have one more class the Vector class, the only difference between Vector class and ArrayList is that the methods of Vector class are synchronized, and hence are thread safe, where as the methods of ArrayList is not synchronized.
Hero Vired
herovired.com › learning-hub › blogs › difference-between-arraylist-and-linkedlist
Difference Between ArrayList and LinkedList in Java : Hero Vired
September 5, 2024 - ArrayList add timing is: 15754300 ns LinkedList add timing is: 52523400 ns ArrayList access timing is: 2217300 ns LinkedList access timing is: 174634999 ns ArrayList remove timing is: 34592300 ns LinkedList remove timing is: 95646500 ns ... So in this example, we have performed a performance test for both ArrayList and LinkedList. The code includes the performance test of adding the elements to the lists, accessing the elements from the lists, and also removing an element from the lists.
Top answer 1 of 5
2
Your test should be like below. In the test code in the original post, you are not actually invoking the method that you are trying to test.
public class UTest
{
@Test
public void testMultipleLast() {
ArrayList<Integer> input = new ArrayList<Integer>(asList(1,1,3,5,7,1,5,9,1));
ArrayList<Integer> result = new ArrayList<Integer>(asList(1,1,3,5,7,1,5,9));
// int x = ?
ArrayList<Integer> actual = SomeClass.removeLastOccurrence(x, input)
assertEquals(result, actual);
}
}
and the removeLastOccurrence() method can do the following
if(list != null && !list.isEmpty()){
list.remove(list.size() - 1);
}
2 of 5
1
It's because you are not removing any elements.
list.get(list.size()-1);
does not remove elements.
use
list.remove(list.size()-1)
instead.