Interview Questions and Answers for 'Java' | Search Interview Question

Interview Questions and Answers - Order By Rating

Q221. Write code to serialize and deserialize an array of strings ?

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q222. Difference between Arrays and ArrayList ?

Core Java

Ans. Both Arrays and ArrayLists are used to store elements. Elements can be either primitives or objects in case of Arrays, but only objects can be stored in Arraylist. Array is a fixed length data structure while arraylist is variable length collection class. Once created, you cannot change the size of the arrays, but arraylists can dynamically resize itself when needed.Another notable difference between Arrays and Arrayslist is that arary is part of core java programming and array list is part of collection classes

Sample Code for arrays arraylist

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve array arraylist array vs arraylist Asked in 7 Companies basic frequent}

Q223. What is the time and space complexity for different operations for arrays ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays}

Q224. Are arrays Thread Safe ?

Core Java

Ans. Yes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays concurrency Asked in 1 Companies}

Q225. How can we check equality for Arrays in Java ?

Core Java

Ans. You call the method java.util.Arrays.equals(Object[] a, Object[] a2)?

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays}

Q226. Are Arrays treated like primitives or like objects in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays}

Q227. Where are arrays stored in memory - stack or heap ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q228. What are jagged arrays ?

Core Java

Ans. an array of different sizes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays jagged arrays}

Q229. What is an anonymous array in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve anonymous arrays}

Q230. What is ArrayStoreException ?

Core Java

Ans. It's an exception that is thrown when we attempt to add value of an incompatible type to an array.

For example -

Object[] strArray = new String[2];
strArray[0] = 5;

In this code, strArray reference of type Object has currently been assigned the String array but at line 2 we are trying to add an integer value.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays ArrayStoreException}

Q231. What is the difference between ArrayIndexOutOfBoundException and ArrayStoreException?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve exception handling}

Q232. Can we use generics with arrays in Java ?

Core Java

Ans. No

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q233. Can we change the size of array once created ?

Core Java

Ans. No. Arrays cannot resize dynamically.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve array array size Basic}

Q234. How arrays work internally ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays}

Q235. Does Java generate .class file for interfaces ?

Core Java

Ans. Yes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve .class file java byte code interfaces}

Q236. Can we declare an Interface with abstract keyword ?

Core Java

Ans. Yes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve abstract keyword}

Q237. Can we declare constructor inside an interface ? Why ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve interface constructor}

Q238. Can we override a non-static method as static in Java ?

Core Java

Ans. No, there is no method overriding with static methods.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q239. Can you prevent overriding a method without using final modifier or without declaring it private ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q240. What is method hiding in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve method hiding}

Q241. Can a class extend itself in Java ?

Core Java

Ans. No

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve inheritance object oriented programming (oops) oops concepts}

Q242. Why Concurrent Collection Classes are fail-fast in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve concurrent collection classes fail fast fail-fast collections collection classes expert}

Q243. What is Lock interface in Java Concurrency API ?

Core Java

Ans. Lock interface provide more extensive locking. They allow more flexible structuring and may support multiple associated Condition objects.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve concurrency api}

Q244. What is context switching wrt Threads in Java?

Core Java

Ans. Context Switching is the process of storing and restoring of CPU state so that Thread execution can be resumed from the same point at a later point of time.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Threads multithreading context switching}

Q245. What are the different ways to avoid multi Threading related problems in Java ?

Core Java

Ans. Synchronization,
Concurrent classes,
Volatile keyword,
Implementing concurrent Lock interface,
Immutable classes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve multithreading threads ways to avoid thread related problems synchronization volatile concurrent collections Intermediate}

Q246. How does multi threading improve performance ?

Core Java

Ans. Every process in it's timeline require different resources. Utilization of resources can be optimized when they are shared among different processes or threads. When one thread is sleeping waiting for a peripheral to complete (e.g. a disk write, or a key press from the keyboard), other threads can continue using processor time and hence would lead to better usage of resources.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve multithreading threads basic frequent}

Q247. Create an event class in Java.

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve event class}

Q248. Which java version supports assertion ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q249. How will you enable or disable assertion for a package during runtime ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q250. Explain Transitive equals contract.

Core Java

Ans. The equals contract is said to be transitive if

obj1.equals(obj2); and obj2(.equals(obj3)

then obj1.equals(obj3) also returns true.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Transitive equals contract rare}

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.