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

Interview Questions and Answers - Order By Rating

Q211. Difference between ArrayList and HashSet ?

Ans. ArrayList is a list , i.e an implementation of List interface whereas HashSet is a Set and an implementation of Set interface.

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

_{Like Discuss Correct / Improve arraylist hashset}

Q212. difference between ArrayList and array ?

Core Java

Ans. ArrayList is a variable length collection class whereas arrays are fixed length primitive structure.

We can use generics with arraylist but not with arrays.

We can store primitive data types within arrays but can't with ArrayList. In ArrayList that needs to be converted to Wrapper objects.

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

_{Like Discuss Correct / Improve arraylist arrays collection classes collections basic frequent}

Q213. Why is String a class in Java ?

Core Java

Ans. 1. Creating a class helps in specifying operations on the Strings like length , sub string , concatenation etc.

2. It acts as a Wrapper class for "Array of Characters" and hence facilitates it's usage in collections, assignment to null.

3. Immutability of String objects facilitates in reuse , security and caching.

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

_{Like Discuss Correct / Improve string class}

Q214. Difference between equals and equalsignorecase in Java ?

Core Java

Ans. "equals" method is the method of object class that needs to be overridden to check object equality. This is not specific to any class like String.

equalsignorecase is the method of String class that provides a definition that ignores the case of characters during comparison.

The only difference between them in String class is that the equals() methods considers the case while equalsIgnoreCase() methods ignores the case during comparison.

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

_{Like Discuss Correct / Improve equals equalsignorecase equals vs equalsignorecase}

Q215. Difference between equals and hashcode in java ?

Core Java

Ans. "equals" is the method of object class which is supposed to be overridden to check object equality. x.equals(y) means the references x and y are holding objects that are equal with the equality defined by the definition of equals method.

Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc. The value received from hashcode() is used as bucket number for storing elements. This bucket number is the address of the element inside the set/map. when you do contains() then it will take the hashcode of the element, then look for the bucket where hashcode points to and if more than 1 element is found in the same bucket (multiple objects can have the same hashcode) then it uses the equals() method to evaluate if object are equal, and then decide if contain() is true or false, or decide if element could be added in the set or not.

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

_{Like Discuss Correct / Improve equals hascode equals vs hascode}

Q216. Difference between equals and compareTo in Java ?

Core Java

Ans. "equals" is the method of object class which is supposed to be overridden to check object equality. x.equals(y) means the references x and y are holding objects that are equal.

The compareTo() method is used for comparing two objects in Java. It is usually defined for the classes whose objects needs to be ordered through Comparable interface or need to be part of an ordered collection like TreeSet or TreeMap.

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

_{Like Discuss Correct / Improve equals compareTo equals vs compareTo}

Q217. Can we use Param Store with AWS Lambda ?

Amazon Web Services (AWS)

Ans. Yes

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

_{Like Discuss Correct / Improve aws param store amazon param store aws lambda amazon lambda}

Q218. Does abstract class have public constructor?

Core Java

Ans. Yes, an abstract class can have a constructor in Java.

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

_{Like Discuss Correct / Improve abstract class public constructor Asked in 1 Companies}

Q219. Explain CloneNotSupportedException ?

Core Java

Ans. If we do not mention, Cloneable Interface to the Class which we want to Clone then we get this exception, only if we try to clone an object

Like:
public class TestClone{
@Override
   protected Object clone() throws CloneNotSupportedException {
      return super.clone();
   }
}

In Main, You try to do:
TestClone clone = new TestClone();

      TestClone clone2 = (TestClone) clone.clone();

You will get CloneNotSupportedException.

Just add -> public class TestClone implements Cloneable {

and things are fixed.

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

_{Like Discuss Correct / Improve exceptions handling cloning}

Q220. Why Hadoop serialized data types are not using in Spark serialization ?

BigData

^{This question was recently asked at 'Tavant Technology'.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 Asked in 1 Companies}

Q221. Explain when you would decide to use open authentication ?

Authentication

Ans. Google OAuth can be used when we want to grant the access of our google credentials to the service provider ( most likely a cloud-based mobile application) by using the option ' Login via Google'

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

_{Like Discuss Correct / Improve open authentication Asked in 1 Companies}

Q222. What does 'variable hoisting' mean?

JavaScript

Ans.

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

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

Q223. How many heaps will be there with 3 threads ?

Core Java

Ans. All threads share a common heap.

Each thread has a private stack, which it can quickly add and remove items from. This makes stack based memory fast, but if you use too much stack memory, as occurs in infinite recursion, you will get a stack overflow.

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

_{Like Discuss Correct / Improve memory management heap memory Asked in 1 Companies}

Q224. Please explain the architecture of our application through a diagram ?

General

^{This question was recently asked at 'Alfresco Software,Ancestry'.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 Asked in 2 Companies}

Q225. What are the disadvantages of binary search trees?

Algorithm

^{This question was recently asked at 'ServiceNow'.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 binary search tree Asked in 1 Companies}

Q226. How to write an iterator for an iterator of iterators?

Core Java

Ans. CustomArrayList myarrayList = new CustomArrayList();
      myarrayList.add("Value 1");
      myarrayList.add("Value 2");
      myarrayList.add("Value 3");

      for (String string : myarrayList) {
         System.out.println(string);
      }

package sample.utils;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class CustomArrayList implements Iterable {

   private ArrayList mylist = new ArrayList();

   public void add(T t) {
      this.mylist.add(t);
   }

   @Override
   public Iterator iterator() {
      return new CustomIterator(mylist);
   }

   class CustomIterator implements Iterator {

      private int indexPosition = 0;
      private List internalList;

      public CustomIterator(List internalList) {
         this.internalList = internalList;
      }

      @Override
      public boolean hasNext() {
         if (internalList.size() >= indexPosition 1) {
            return true;
         }
         return false;
      }

      @Override
      public E next() {
         E val = internalList.get(indexPosition);
         indexPosition ;
         return val;
      }

   }

}

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

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

Q227. Do you think it's a good practice to keep passwords in config files ?

Solution

Ans. We can keep them in config as encrypted values.

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

_{Like Discuss Correct / Improve}

Q228. Can we keep application configuration at different places and what could be the consideration for choosing multiple places for doing so ?

Design

Ans. Yes an application can have configuration stored at multiple places. Factors that could facilitate such a design could be

1. Type of config information - We may have a case to store confidential information differently than other regular config value

2. Environment - We may like to have a base config ( defined in application package ) and then a different override mechanism in different environments.

3. Centralization - Sometime some configs need to be shared across application and hence centralized.

4. Testing - Testing against config may not be possible in some enviornments in certain cases and hence additional config store might be kept for testing purpose only.

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

_{Like Discuss Correct / Improve Design Solution}

Q229. How would you test a Twitter application ?

Testing

^{This question was recently asked at 'Slalom'.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 solution testing Asked in 1 Companies}

Q230. What is the minimum number of tables required to perform a SQL join?

Database

Ans. 1 , We can do self join

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

_{Like Discuss Correct / Improve sql join Asked in 1 Companies}

Q231. why is "".equals(str); safer than str.equals("")?

Core Java

Ans. str.equals("") this statement will throw NullPointerException if str is null where as "".equals(str) works fine even if str is null

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

_{Like Discuss Correct / Improve equals method Asked in 1 Companies}

Q232. Which maven commands you usually work with ?

Maven

^{This question was recently asked at 'Akvelon'.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 maven Asked in 1 Companies}

Q233. How can you prove your honesty ?

General

^{This question was recently asked at 'Gallup'.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 Asked in 1 Companies}

Q234. If you are asked to develop a financial system, how would you make sure that there are proper checks , balances and audits ?

Solution

^{This question was recently asked at 'BzzAgent'.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 Design Security Asked in 1 Companies}

Q235. How can we take snapshots and track changes to environment variables in Elastic Beanstalk or Lambda ?

Amazon Web Services (AWS)

Ans. We can use AWS Config

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

_{Like Discuss Correct / Improve aws elastic beanstalk amazon elastic beanstalk aws lambda aws serverless computing amazon cloud serverless computing amazon lambda}

Q236. Can a constructor be declared static ? Why ?

Core Java

Ans. No.

When we declare a method static, it means that "this belongs to class as whole and not particular instance". The whole purpose of constructor is to initialize a object and hence there is no sense having static constructor.

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

_{Like Discuss Correct / Improve constructor static static constructor Asked in 1 Companies}

Q237. Can constructors be final ?

Core Java

Ans. No. They are never inherited and therefore are not subject to hiding or overriding.

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

_{Like Discuss Correct / Improve constructor final final constructor Asked in 1 Companies}

Q238. Can we load Yaml files into AWS DynamoDB ?

Amazon Web Services (AWS)

Ans. No

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

_{Like Discuss Correct / Improve aws dynamodb aws nosql database amazon cloud nosql database}

Q239. Which is a better way to keep environment specific configuration in AWS Lambda - Environment Variables or external service like S3 or RDS ?

Amazon Web Services (AWS)

Ans. Possible Answer - Env variable or use parameter store

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

_{Like Discuss Correct / Improve aws lambda aws serverless computing amazon cloud serverless computing amazon lambda}

Q240. How do you manage environment specific configuration for your lambda functions ?

Amazon Web Services (AWS)

Ans. We are using Yaml for initializing configuration and Environment Variables for overriding them.

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

_{Like Discuss Correct / Improve aws lambda aws serverless computing amazon cloud serverless computing amazon lambda}

Search Interview Questions

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