Java List Interface

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

Last Updated : Apr 1, 2025

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Question 1

Which of the following classes does NOT implement the List interface?

A
ArrayList
B
LinkedList
C
HashSet
D
Vector

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Question 2

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

A
5
B
10
C
16
D
0

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Question 3

What will be the output of the following code?

Java

import java.util.*;
public class Test {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        list.add(1); list.add(2); list.add(3);
        list.add(1, 10);
        System.out.println(list);
    }
}

A
[1, 2, 3, 10]
B
[1, 10, 2, 3]
C
Compilation Error
D
Runtime Error

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Question 4

Which List implementation provides the best performance for random access operations?

A
LinkedList
B
ArrayList
C
Vector
D
Stack

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Question 5

Which of the following statements is true about LinkedList?

A
It uses an array internally for storage
B
It allows fast random access using indexing
C
It has efficient insertions and deletions at both ends
D
It does not support null values

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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) {
        List<Integer> list = new LinkedList<>();
        list.add(10);
        list.add(20);
        list.remove(0);
        System.out.println(list);
    }
}

A
[10]
B
[20]
C
Compilation Error
D
Runtime Error

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Question 7

What is the time complexity of ArrayList.add(index, element) operation in the worst case?

A
O(1)
B
O(log n)
C
O(n)
D
O(n log n)

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Question 8

Which of the following List implementations is synchronized?

A
ArrayList
B
Vector
C
LinkedList
D
CopyOnWriteArrayList

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Question 9

Which method is used to obtain a sublist from an existing List?

A
list.getSubset(start, end)
B
list.extract(start, end)
C
list.subList(start, end)
D
list.split(start, end)

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Question 10

What will be the output of the following code?

Java

import java.util.*;
public class Test {
    public static void main(String[] args) {
        List<String> list = Arrays.asList("A", "B", "C");
        list.add("D");
        System.out.println(list);
    }
}

A
[A, B, C, D]
B
[A, B, C]
C
Compilation Error
D
Runtime Error

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