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Java ArrayList

Here are 10 essential multiple-choice questions on Java ArrayList, covering key concepts.

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Question 1

What is the default initial capacity of an ArrayList when it is created using the no-arg constructor?

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Question 2

What will be the output of the following code?

Java

import java.util.*; public class Test {     public static void main(String[] args) {         ArrayList<Integer> list = new ArrayList<>();         list.add(1);         list.add(2);         list.add(3);         list.remove(1);         System.out.println(list);     } }

[1, 3]
[2, 3]
[1, 2]
[1, 2, 3]

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Question 3

Which method of ArrayList is used to add an element at a specific index?

addAtIndex()
insert()
add()
add(index, element)

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Question 4

What will be the result of the following code?

Java

import java.util.*; public class Test {     public static void main(String[] args) {         ArrayList<Integer> list = new ArrayList<>();         list.add(10);         list.add(20);         list.add(30);         list.add(40);         list.set(2, 50);         System.out.println(list);     } }

[10, 20, 50, 40]
[10, 20, 30, 40]
[10, 20, 40, 50]
[50, 20, 30, 40]

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Question 5

Which of the following methods is used to check if an ArrayList is empty?

isEmptyList()
isNull()
isEmpty()
empty()

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Question 6

What will be the output of the following code?

Java

import java.util.*; public class Test {     public static void main(String[] args) {         ArrayList<String> list = new ArrayList<>();         list.add("Apple");         list.add("Banana");         list.add("Cherry");         list.add("Date");         list.remove("Banana");         System.out.println(list);     } }

[Apple, Cherry, Date]
[Apple, Banana, Cherry, Date]
[Banana, Apple, Cherry, Date]
[Apple, Cherry, Date, Banana]

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Question 7

Which of the following methods returns the number of elements in an ArrayList?

size()
length()
count()
getSize()

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Question 8

What will happen if you try to access an element with an index greater than the size of the ArrayList?

It throws an ArrayIndexOutOfBoundsException
It throws a NoSuchElementException
It returns null
It throws an IndexOutOfBoundsException

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Question 9

What is the time complexity of the add() method in an ArrayList (amortized case)?

O(1)
O(n)
O(log n)
O(n^2)

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Question 10

What is the maximum capacity of an ArrayList?

1000 elements
The maximum value of an integer
2^31 - 1 elements
There is no maximum capacity

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