You have ArrayList all wrong,
- You can't have an integer array and assign a string value.
- You cannot do a
add()method in an array
Rather do this:
List<String> alist = new ArrayList<String>();
alist.add("apple");
alist.add("banana");
alist.add("orange");
String value = alist.get(1); //returns the 2nd item from list, in this case "banana"
Indexing is counted from 0 to N-1 where N is size() of list.
W3Schools
w3schools.com › java › java_arraylist.asp
Java ArrayList
An ArrayList keeps elements in the same order you add them, so the first item you add will be at index 0, the next at index 1, and so on.
Oracle
docs.oracle.com › javase › 8 › docs › api › java › util › ArrayList.html
ArrayList (Java Platform SE 8 )
April 21, 2026 - the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element ... Returns a shallow copy of this ArrayList instance.
A better way to find the index of an element in an array?
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August 27, 2022I need help to understand how Arraylist works in java
Arraylist.add(x) More on reddit.com
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March 26, 2025Videos
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ArrayList / Lists - Full Tutorial - Java Data Structures Tutorial ...
09:40
Learn Java arraylists in 9 minutes! 📃 - YouTube
01:37
#121 Java ArrayList indexOf() – Find Element Position with Examples ...
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Does ArrayList has indexing in Java (Core Java Interview Question ...
Traversing a Java ArrayList (Printing an ArrayList) - YouTube
Top answer 1 of 7
110
You have ArrayList all wrong,
- You can't have an integer array and assign a string value.
- You cannot do a
add()method in an array
Rather do this:
List<String> alist = new ArrayList<String>();
alist.add("apple");
alist.add("banana");
alist.add("orange");
String value = alist.get(1); //returns the 2nd item from list, in this case "banana"
Indexing is counted from 0 to N-1 where N is size() of list.
2 of 7
20
Read more about Array and ArrayList
List<String> aList = new ArrayList<String>();
aList.add("apple");
aList.add("banana");
aList.add("orange");
String result = alist.get(1); //this will retrieve banana
Note: Index starts from 0 i.e. Zero
- Resource
GeeksforGeeks
geeksforgeeks.org › java › arraylist-get-method-java-examples
ArrayList get(index) Method in Java with Examples - GeeksforGeeks
December 10, 2024 - The get(index) method of ArrayList in Java is used to retrieve the element at the specified index within the list.
Codecademy
codecademy.com › docs › java › arraylist › .indexof()
Java | ArrayList | .indexOf() | Codecademy
February 12, 2023 - The .indexOf() method returns the index of the first occurrence of the specified element in an ArrayList.
Coderanch
coderanch.com › t › 622130 › java › ArrayList-Find-Indexes-Occurrence
ArrayList: Find all Indexes of an Occurrence [Solved] (Beginning Java forum at Coderanch)
October 19, 2013 - Well done It would have been easier had the indexOf() method been overloaded to take a starting index. ... You can of course subclass ArrayList and add that method.
W3Schools
w3schools.com › java › ref_arraylist_indexof.asp
Java ArrayList indexOf() Method
The indexOf() method returns the position of the first occurrence of a value in the list.
Reddit
reddit.com › r/javahelp › a better way to find the index of an element in an array?
r/javahelp on Reddit: A better way to find the index of an element in an array?
August 27, 2022 -
Currently the best way I have found is to typecast the array into an ArrayList, and using ArrayList's method .indexOf to get the index, for e.g:
import java.util.Arrays;
int[] arr = {2,3,4,5};
Arrays.asList(arr).indexOf(4); // returns 2Is this the best way? Or unnecessary wrapping?
Top answer 1 of 4
7
That way doesn't work. int[] can't be wrapped up as a List via List Arrays.asList(T...) - you'll get a List back (with a single element). If the array is sorted you can use Arrays.binarySearch(arr, 4) - if it is not sorted then you've got fewer choices. Most efficient is probably... int index = -1; for (int i = 0; i < arr.length; i++) { if (arr[i] == x) { index = i; break; } } But you could also do int index = IntStream.range(0, arr.length) .filter(i -> arr[i] == x) .findFirst() .orElse(-1); If the array was spectacularly large, this might pay off in parallel (but the findFirst limits this as it forces some sequencing to the parallel operation - findAny would help). Generally I'd just make a method to do the for-loop (or try to avoid needing to scan in the first place - not always possible).
2 of 4
3
If you're doing this, why not just use Lists instead of arrays?
CodeHS
codehs.com › tutorial › 13901
Tutorial: ArrayLists in Java | CodeHS
Learn how to create and use ArrayLists in your programs!
GeeksforGeeks
geeksforgeeks.org › java › arraylist-in-java
ArrayList in Java - GeeksforGeeks
Automatic Resizing: When the internal array becomes full, the ArrayList automatically increases its capacity by creating a new larger array and copying the existing elements into it. Index-Based Access: Elements are stored in contiguous memory locations, allowing fast access using indexes (e.g., get(index)), typically in O(1) time complexity.
Published May 12, 2026
GeeksforGeeks
geeksforgeeks.org › dsa › dsa-in-java
DSA in JAVA - GeeksforGeeks
October 8, 2025 - This beginner-friendly guide covers Data Structures and Algorithms (DSA) in Java, including built-in structures like arrays, strings, ArrayList, HashMap, HashSet, and user-defined structures such as linked lists, stacks, queues, trees, heaps, and graphs.
W3Schools
w3schools.com › java › java_list.asp
W3Schools.com
You can access elements by their index, add duplicates, and maintain the insertion order. Since List is an interface, you cannot create a List object directly. Instead, you use a class that implements the List interface, such as: ArrayList - like a resizable array with fast random access
CODEDOST
codedost.com › home › java › collections in java › get(int index) method of arraylist in java
get(int index) method of ArrayList in JAVA | CODEDOST
July 25, 2021 - In order to retrieve an element from an arrayList, get(int index) method is used. get(int index) method returns the value at the specified index and if index is outside the range, it will throw an IndexOutOfBounds Exception.
Simon Hartcher
simonhartcher.com › posts › 2026-04-08-applying-programming-without-pointers-to-an-mbox-indexer-using-zig
Applying "Programming Without Pointers" to an mbox indexer using Zig | Simon Hartcher
April 8, 2026 - I find them fun to write and very easy to comprehend. Due to the simple data structures of the index, writing takes zero allocations. And because of the file design and PWP, reading only requires two! One for the message_ids array list, and one for the locations hash map.
DEV Community
dev.to › riansyah › javabite-arraylist-and-linkedlist-367b
ArrayList and LinkedList in Java - DEV Community
December 29, 2024 - ArrayList An ArrayList is like a dynamic array. It stores elements by their index, so you can quickly jump to any element you want.
Reddit
reddit.com › r/learnprogramming › i need help to understand how arraylist works in java
r/learnprogramming on Reddit: I need help to understand how Arraylist works in java
March 26, 2025 -
Example I have made an arraylist of 3 elements.(0,1,2 indexes)
I want to add another element in the 4th index, will java automatically fill the empty indexes or do I have to run a while loop in order to fill those empty spaces?
Baeldung
baeldung.com › home › java › java list › inserting an object in an arraylist at a specific position
Inserting an Object in an ArrayList at a Specific Position | Baeldung
April 3, 2025 - If we want to add an element to a specific position to an ArrayList we can use the add(int index, E element) method which is provided through the implementation of the interface of List<E>. This method let us add an element at a specific index.
How to do in Java
howtodoinjava.com › home › collections framework › java arraylist › java arraylist.indexof()
Java Arraylist.indexOf() - Get Element Index - HowToDoInJava
January 13, 2023 - Note that string “alex” is present in the list 3 times, but the method returns the index of the first occurrence. Please note that list indices start from 0. ArrayList<String> list = new ArrayList<>(Arrays.asList("alex", "brian", "charles","alex",","alex","harry")); int index = list.indexOf("alex"); System.out.println(index);
LeetCode
leetcode.com › problems › two-sum-ii-input-array-is-sorted
Two Sum II - Input Array Is Sorted - LeetCode
7,11,15], target = 9 Output: [1,2] Explanation: The sum of 2 and 7 is 9. Therefore, index1 = 1, index2 = 2.
Microsoft Learn
learn.microsoft.com › ru-ru › dotnet › api › system.collections.arraylist.indexof
ArrayList.IndexOf Метод (System.Collections) | Microsoft Learn
Выполняет поиск указанного Object и возвращает отсчитываемый от нуля индекс первого вхождения в течение всего ArrayList. public: virtual int IndexOf(System::Object ^ value);