Java LinkedHashMap MCQ Questions and Answers

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Hey friends! Welcome to our blog post titled Java LinkedHashMap MCQs. It’s a fun way to test your skills and learn something cool about Java programming!

Java LinkedHashMap is a special type of collection that stores items in a map based on the order they were added. It’s like a mix between a hash table and a linked list. This makes it super useful when you need to keep your data in a specific order.

So, if you’re curious about how LinkedHashMap works or want to sharpen your Java skills, this is the place to be. Dive into these questions with us and let’s explore the interesting world of Java LinkedHashMap together. Ready to get started? Let’s go!

1. What is a LinkedHashMap in Java?

a) A type of array
b) A type of linked list
c) A type of set
d) A hash table and linked list implementation of the Map interface

Answer:

d) A hash table and linked list implementation of the Map interface

Explanation:

LinkedHashMap is a Map implementation that maintains a linked list of the entries in the map, in the order in which they were inserted.

2. How does LinkedHashMap maintain the order of elements?

a) Using a hash table
b) By sorting the keys
c) Through a doubly-linked list
d) Using an array

Answer:

c) Through a doubly-linked list

Explanation:

LinkedHashMap maintains the insertion order of its entries through a doubly-linked list.

3. Can a LinkedHashMap contain duplicate keys?

a) Yes
b) No
c) Only integer keys can be duplicated
d) Only string keys can be duplicated

Answer:

b) No

Explanation:

Like any other Map implementation, LinkedHashMap cannot have duplicate keys.

4. What is the default initial capacity of a LinkedHashMap?

a) 8
b) 10
c) 12
d) 16

Answer:

d) 16

Explanation:

The default initial capacity of a LinkedHashMap is 16.

5. Which method is used to access elements in a LinkedHashMap?

a) access()
b) get()
c) retrieve()
d) find()

Answer:

b) get()

Explanation:

The get() method is used to access elements in a LinkedHashMap by their key.

6. Can a LinkedHashMap contain null values and null key?

a) Yes
b) No
c) Only null values, not null key
d) Only null key, not null values

Answer:

a) Yes

Explanation:

LinkedHashMap allows one null key and multiple null values.

7. What is the time complexity of basic operations like put and get in a LinkedHashMap?

a) O(1)
b) O(log n)
c) O(n)
d) O(n^2)

Answer:

a) O(1)

Explanation:

Basic operations like put and get have a constant time complexity in a LinkedHashMap.

8. How does a LinkedHashMap differ from a HashMap in Java?

a) LinkedHashMap is synchronized
b) LinkedHashMap maintains insertion order
c) LinkedHashMap allows duplicate keys
d) LinkedHashMap uses less memory

Answer:

b) LinkedHashMap maintains insertion order

Explanation:

The main difference between LinkedHashMap and HashMap is that LinkedHashMap maintains the insertion order of entries.

9. How do you remove all entries from a LinkedHashMap?

a) clear()
b) removeAll()
c) empty()
d) deleteAll()

Answer:

a) clear()

Explanation:

The clear() method is used to remove all the mappings from a LinkedHashMap.

10. Is the iteration order over a LinkedHashMap predictable?

a) Yes, it follows insertion order
b) No, it's random
c) Yes, it follows natural ordering
d) No, it follows hash code ordering

Answer:

a) Yes, it follows insertion order

Explanation:

The iteration over a LinkedHashMap is predictable as it follows the insertion order of the entries.

Related MCQ (Multiple Choice Questions) :

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