Java Collection Interview Questions
Top Java Collection Interview Questions to Prepare for Success
Java Collection Interview Questions
During a Java collection interview, candidates may be asked about different types of collections in Java such as List, Set, and Map, and their differences and use cases. Interviewers may also inquire about common collection classes and interfaces, and the advantages of using each type of collection in various scenarios. Additionally, questions can relate to the differences between ArrayList and LinkedList, how HashMap works internally, and how to iterate over collections efficiently. Candidates may also be asked about the importance of generics in collections, the benefits of concurrency in collections, and the differences between synchronized and concurrent collections. It is essential for candidates to demonstrate a good understanding of Java collections and their practical implementation during such interviews.
To Download Our Brochure: https://www.justacademy.co/download-brochure-for-free
Message us for more information: +91 9987184296
1 - What are the main interfaces in the Java Collection framework?
The main interfaces in the Java Collection framework are List, Set, Queue, Deque, Map. These interfaces provide different ways to store and manipulate groups of objects in Java.
2) What is the difference between List and Set in Java?
List in Java is an ordered collection of objects that allows duplicate elements, while Set is an unordered collection of unique elements. List maintains the insertion order, while Set does not guarantee the ordering of elements.
3) Explain the difference between ArrayList and LinkedList in Java.
ArrayList in Java is implemented as a resizable array, which provides fast random access but slower insertion and deletion. LinkedList is implemented as a doubly linked list, which offers fast insertion and deletion but slower random access.
4) What is the purpose of the Map interface in Java?
The Map interface in Java represents a collection of key value pairs and does not allow duplicate keys. It provides methods to associate keys with values and retrieve values based on keys.
5) What is the difference between HashMap and HashTable in Java?
HashMap in Java is not synchronized and allows null keys and values, while HashTable is synchronized and does not allow null keys and values. HashMap is generally preferred for non thread safe applications, while HashTable is used in multi threaded environments.
6) How does the HashSet ensure uniqueness of elements in Java?
HashSet in Java uses the hashCode() and equals() methods to ensure the uniqueness of elements. When an element is added to a HashSet, its hashCode is calculated, and if there is already an element with the same hashCode, the equals() method is used to check for equality.
7) Explain the concept of fail fast and fail safe iterators in Java.
Fail fast iterators in Java throw ConcurrentModificationException if the collection is modified while iterating. Fail safe iterators, on the other hand, do not throw exceptions but operate on a cloned copy of the collection to avoid concurrent modification issues.
8) What is the difference between Iterator and ListIterator in Java?
Iterator in Java is used to iterate over collections in a forward direction only, while ListIterator is used to iterate over Lists in both forward and backward directions. ListIterator provides additional methods for navigation within a List.
9) How does the ConcurrentHashMap achieve thread safety in Java?
ConcurrentHashMap in Java achieves thread safety by partitioning the Map into segments using a technique called lock striping. This allows multiple threads to read and write to different segments concurrently, improving performance in multi threaded applications.
10) What is the purpose of the Collections class in Java?
The Collections class in Java provides utility methods for working with collections, such as sorting, shuffling, searching, and synchronizing collections. It contains static methods for manipulating collections and provides convenience methods for common collection operations.
Browse our course links : https://www.justacademy.co/all-courses
To Join our FREE DEMO Session: Click Here
Contact Us for more info:
- Message us on Whatsapp: +91 9987184296
- Email id: info@justacademy.co
Marketing Interview Questions And Answers
Java Interview Questions And Answers For Freshers
Cracking The Coding Interview Python
