Interview Questions and Answers for 'This' | Search Java Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com
Share

Search Interview Questions


 3235 questions in repository.
 There are more than 200 unanswered questions.
Click here and help us by providing the answer.
 Have a video suggestion.
Click Correct / Improve and please let us know.
Label / Company      Label / Company / Text

   



Interview Questions and Answers for 'This' - 24 question(s) found - Order By Newest

Very frequently asked. Among first few questions in almost all interviews. Among Top 5 frequently asked questions. Frequently asked in Indian service companies (HCL,TCS,Infosys,Capgemini etc based on multiple feedback )
  Q1. Difference between == and .equals() ?Core Java
Anonymous
Ans. "equals" is the method of object class which is supposed to be overridden to check object equality, whereas "==" operator evaluate to see if the object handlers on the left and right are pointing to the same object in memory.

x.equals(y) means the references x and y are holding objects that are equal. x==y means that the references x and y have same object.

Sample code:

String x = new String("str");
String y = new String("str");

System.out.println(x == y); // prints false
System.out.println(x.equals(y)); // prints true

  Sample Code for equals

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


   Like      Discuss      Correct / Improve     java   string comparison   string   object class   ==    equals   object equality  operator     Ebay  Cerner  GuideWire  Expeditors Associate  Revature  SAIC  ValueLabs  Realty Redefined  Bank Of America  Capgemini  HCL Technologies  Goldman Sachs  Symmetric Corp  Backstop Solutions  Frontier  IQOR   Science  Vanguard  eClinicalWorks  Experticity  Blue Cross and Blue Shield of Kansas  ComTrade  Banja Luka  Overstock.com  Intrasoft International  IBM  Apex Systems  infoview technologies  Ebix  Cumulus Systems  Nakisa  United HealthGroup (UHG)  Sopra Steria  TrueCaller  Mphasis  Amdocs  T & A Hr Solutions  End2End Catalyst  Code Garage Tech  IQuest Management Consultants  Indianmesh pvt ltd  Netsmartz  Meander Software  UrbanPro.com  Netrovert Software  T & A Hr Solutions  Zscaler  Maven Wave Partners  Basware India  Emerson  GCE solutions  SmartData Enterprise  Shivark Virtual Academy  FinXera  Sampoorna Consultants  Samridhi  KKA Technologies  bebo technologies  Closeloop Technologies  DamcoSoft  Swar Yantra Technologies  SK VedaInfo Universal  Trantor Software  IT HAT Consulting  Kindlebit Solutions  Mann McGlynn  AmrtData Enterprises  Riconz Technologies  Embryo Software Solution  Corporate Stalwarts  Varite  Mirror Consultancy Service  Wing Global IT Service  Regence  Adpearance  IGNW  Centizen  Flexton  Syntel  Kaiser Permanente  SkiData  New Relic  McKesson  Finastra  Pivotal  UST Global  Morgan Stanley  Kroger  Genesys  Guardian Life  SynergisticIT  Leidos  Expeditors Associate  Polycom  Compass  Point ClickCare  Expedia  Equal Experts  Dimentrix  Intellect Design Arena  Epam Systems  Qualys  Instacart  ThoughtWorks  Maxgen Technologies  Aayansh Germinate  Principal Financial Group  NineScript Technologies  Nihilent  infrasoft technologies  e-Zest Solutions  Krawler Inc  FundTech  BNT SOFT  SAPsphinx Infotech  KinderTouch  Accede Software Solutions  LeadLake  Emerson  Xoriant  Citrix  Anonymous Content  GS Lab  Thermax  Saama Technologies  Fresherworld.com  Nityo Infotech  Sanofi  Innoplexus  Sears IT & Management Services   National Stock Exchange of India  Accelya Kale  Tudip Technologies  ITSource Technologies  Sela Technology Solutions  Eternus Solutions  Raja Software Labs  Leo TechnoSoft  Shubham Housing Development Finance  Serene Corporation  Leo Technosoft  Questionpro  Sparken IT Solutions  Capsilon  JetSynthesys  MangoSpring  Subway  Arezzo Sky  Lenco Diagnostic Laboratories  Finlogic Technologies  Maxxton  Cerillion  Applus+  XOYAL  Acloudzyn Technologies  ITYX  Tej IT Solutions  Transworld Compressor Technologies  Deskera  Ebaotech  Kahuna Systems  Kimaya Infotech  SSP Technology  Boston Byte  Bonellisoft  Rack Infotech  Intellection Software and Technologies  OMVSAB IT Solutions  ProductDossier  Soft Infology  Systems Plus Transformations  StackMint  HeadInfotech India  EffortSys  KasNet Technologies  Java City  iSynergy TechSys  Unisoft Technologies  Servient  ThinkQuotient Software  Medline Industries  Ascent Cyber Solutions  Proto-T Solutions  Tinker Technologies  Censhare  Proto-T Solutions  Henx International Technologies  AlightHub Consulting Services  Perpetual Infotech  BestoSys  Infiniti Infosystems  Torqus  Spectrum Tech System  OreInfo  Sanvi Softech  Neptune Solutions  XTime  Web Hub Technology  Coin Technologies  Paramount Pictures  Rocklike DMS  Implant Technosoft Solutions  Nabla Infotech  Predikly  Godwit Technologies  Kanaka Consulting  Aarnum Technologies  Ganesh Kapure  Abhinav Digicompsoft Services  Shoffex.com  Online Training Solutions  A Plus Tree  OMM Software Innovation  Tanish Infotech Solution  Zinist Software  Mobile Sutra  Playpixel Infosystem  SunGuard  Nihilent  Siemens PLM Software  Maxgen Technologies  Nitor Infotech  Mediaocean  Yagna iQ  Sigma Systems  Ethon  The Permanente Medical Group  Reliance Industries  MindCraft Software  ABM Knowledgeware  Trutech Web Solutions  Nikhil R Gupta & Associates  eMeasurematics  NovelERP Solutions  Web Element Solutions  HDFC Bank  Qualcomm  Intellect Design Arena  Diebold Nixdorf  Sharekhan  Pepperfry  IRIS Business Services  Wind World  ZEDO  Loylty Rewardz Mngt  C2L Biz  Chenoa Information Services  Insolutions Global  Vakrangee Softwares  Celusion Technologies  Currencies Direct  Zenith System Solutions  Base Information Management  Exponentia DataLabs  Realty Redefined  Constaccent  Neoquant Solutions  Aureus Analytics  Planfirma Technologies  Pawaa Software  iBhejo  Fairfax County Virginia  American Conservation Experience  Hari Krishna Exports  Core Education & Technologies   Nishat Mills  Industrial Market Place  Krisnela Technologies  Swissclear Global  Samyak Software  Professional Access  Nexstep Infotech  Concerto Software  Viral Technologies  Silverwing Technologies  Gcom Software Inc  Accel Frontline  Atom Technologies  Blue Star Infotech  Cynapse  Datamatics Global Services  Flytxt Mobile Solutions  Persistent Systems  Onmobile Global  Trianz  Sasken  WNS Global Services  Tavant technology  Edz Infomatics      basic        frequent

Try 6 Question(s) Test


  Q2. What is a Lambda Expression ? What's its use ?Core Java
Admin
info@buggybread.com
Ans. Its an anonymous method without any declaration.

Lambda Expression are useful to write shorthand Code and hence saves the effort of writing lengthy Code.

It promotes Developer productivity, Better Readable and Reliable code.

  Sample Code for lambda

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


   Like      Discuss      Correct / Improve     java   java8   lambda expression   architecture     Axxess  CACI  ZonOff  Dell India  Wellington Management  N26  Lithium Technologies  DST Systems  Overstock  Sofi  JP Morgan  HCL Technologies  Infosys  Wipro  Accenture  Accenture India  Eurofins  Yodlee  AvenData GmbH  Sapient Global Markets  Walmart  Ebay  Goldman Sachs  Foundation Software  HSBC Holdings  Wells Fargo  Marlabs  ZooPlus  Elastic Path  CardConnect  WealthFront  WorldAware  SpredFast  Mobileum  eGym  EnelX  Kroger  GFT Technoligies  Tyro Payments  Mindtree  KocharTech  Bharti Airtel  Tech Mahindra  Patni Computers  L&T Infotech  Mphasis  Mindtree  Hexaware  Collabera  3i Infotech  IGate  Kpit Technologies  NIIT Technologies  Trianz  Persistent Systems  IT Asset  1-800 contacts      expert        frequent

Try 1 Question(s) Test


 Q3. What are the common uses of "this" keyword in java ?Core Java
Anonymous
Ans. "this" keyword is a reference to the current object and can be used for following -

1. Passing itself to another method.

2. Referring to the instance variable when local variable has the same name.

3. Calling another constructor in constructor chaining.

  Sample Code for this keyword

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

   Like      Discuss      Correct / Improve     java   this   object reference   constructor chaining      intermediate        rare

Try 3 Question(s) Test


 Q4. Can we use both "this()" and "super()" in a constructor ?Core Java
Anonymous
Ans. No, because both this and super should be the first statement.

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

   Like      Discuss      Correct / Improve     java   oops  this   super   constructor      intermediate        rare

Try 2 Question(s) Test


Very Frequently asked. Have been asked in HCL Technologies very frequently ( based on 3 feedback ). Among first few questions in many interviews.
  Q5. Differences between abstract class and interface ?Core Java
Admin
info@buggybread.com
Ans. Abstract classes can have both abstract methods ( method declarations ) as well as concrete methods ( inherited to the derived classes ) whereas Interfaces can only have abstract methods ( method declarations ).

A class can extend single abstract class whereas it can implement multiple interfaces.

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


   Like      Discuss      Correct / Improve     java   classes   abstract class   interfaces     GlobalLogic  HCL Technologies  Tata Consultancy (TCS)  Infosys  Wipro  Mindtree  CapitalOne  Accenture  Accenture India  IBM India  Infoview Technologies  Salesforce  AT&T  United Health Group (UHG)  Verilogue  Amazon  Expeditors  Syntel  SalesForce  Cornerstone OnDemand  Expedia  OLA  NSF International  Copper Mobile  Think Future Technologies  MorphoTrust  Global Healthcare  Prodigious  Internet Brands  SciQuest  arvato Systems  iCIMS  Ideas2IT  virtusa polaris  Vitech Systems  Cognizant (CTS)  Speridian Technologies  Ojas Innovative Technologies  SWC Technology Partners  Cricbuzz  Jean Martin  Capgemini  Virtusa  ECI Telecom   Aptify   Crossover  ample softech  Metanoia software solutions  Overstock.com  Unic Sol India  Experis India  Intellect Design Arena  Sarathi Softech  Transorg Analytics  Cibersites India  Resource Weaver  Indium Software  Kone Elevator  Merkur Gaming  Prama Hikvision  Gurucul Solutions  e-Zest Solutions  ReadMind Info Services  Equator Business Solutions      basic        frequent


 Q6. Difference Between this() and super() ?Core Java
Admin
info@buggybread.com
Ans. 1.this is a reference to the current object in which this keyword is used whereas super is a reference used to access members specific to the parent Class.

2.this is primarily used for accessing member variables if local variables have same name, for constructor chaining and for passing itself to some method whereas super is primarily used to initialize base class members within derived class constructor.

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

   Like      Discuss      Correct / Improve     java   oops   class   objects   inheritence   constructor   this   super     Thrymr Software

Try 1 Question(s) Test


 Q7. What is "this" keyword used for ?
Anonymous
Ans. Used to represent an instance of the class in which it appears.

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

   Like      Discuss      Correct / Improve     java   oops   java keywords   this   basic interview question      basic        frequent


 Q8. Why can't we use this in static context ?Core Java
Admin
info@buggybread.com
Ans. Static methods can be called using instance references wherein this would have made sense but static method can also be called using Class name wherein this would mean nothing and hence forbidden.

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

   Like      Discuss      Correct / Improve     java   static methods   this keyword

Try 2 Question(s) Test


 Q9. Can we use "this" within static method ? Why ?Core Java
Admin
info@buggybread.com
Ans. No. Even though "this" would mean a reference to current object id the method gets called using object reference but "this" would mean an ambiguity if the same static method gets called using Class name.

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

   Like      Discuss      Correct / Improve     java   oops   static   this keyword   this   yes no   why questions      intermediate



Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here



 Q10. Difference between Assert and Verify ?Testing
admin
info@buggybread.com
Ans. Assert works only if assertions ( -ea ) are enabled which is not required for Verify.Assert throws an exception and hence doesn't continue with the test if assert evaluates to false whereas it's not so with Verify.

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

   Like      Discuss      Correct / Improve     assert   junit   mockito   verify   testing   unit testing     Fifth Third Bank  Infionic Software  Thomson Reuters  barclays  JP Morgan


Very frequently asked. Usually followed by questions related to private constructor and synchronized access. Frequently asked in JPMorgan and TCS (Based on 2 feedback)
  Q11. Explain Singleton Design Pattern ?Design
Admin
info@buggybread.com
Ans. http://www.buggybread.com/2014/03/java-design-pattern-singleton-interview.html

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

   Like      Discuss      Correct / Improve     java   design pattern   singleton   at&t   ebay  fidelity india  united healthcare india     JP Morgan  Tata Consultancy (TCS)  HCL Technologies  Wipro  Infosys  Tibco  Edline  JPMorgan Chase  Sabre  Bank Of America India  Fidelity  Samsung India  Robert Bosch India  ZapCom  Goldman Sachs India  Eze Software  ZapCom  Dailymotion  Netflix  CenturyLink  Misfit  TSYS  ECI Telecom  Dealogic  Robert Bosch  Redolent  EFI  CSX  Prolific  Validus  Birlasoft  AdNovum  NCR  Ray Business Technologies  Nagravision  Unify  SLK Group  DBS Bank   Razorthink  GST Global  USAA  Ray Technologies  Ray Business Technologies (Raybiztech)  Raybiztech  Deloitte  EPAM      intermediate        frequent


 Q12. In majority of the situations it won't make much sense whether you append this with the instance method call.Can you tell a situation wherein this keyword would make sense in a instance method ? Core Java
admin
info@buggybread.com
Ans. Within instance method of the parent class that has other multiple methods that have been overridden by the derived classes.

In such case a simple method call from the common method will always be made to the method definition in the parent class. But If we use this.methodCall , this will be polymorphic and will be made to the respective derived object overriding method.

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

   Like      Discuss      Correct / Improve     java   this keyword   java keywords


  Q13. What is Jenkins ?Jenkins
Admin
info@buggybread.com
Ans. It is a continuous integration tool written in Java.

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

   Like      Discuss      Correct / Improve     java   jenkins     Lithium Technologies  Adtech  Deloitte  Netcracker Technology  Alcatel Lucent  American International Group (AIG)      Basic        frequent


 Q14. Which of the following is not the use of this keyword ?

a. Passing itself to another method
b. To call the static method
c. Referring to the instance variable when local variable has the same name
d. Calling another constructor in constructor chaining
Anonymous
Ans. To call the static method

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

   Like      Discuss      Correct / Improve     this   this keyword   java


 Q15. Does compiler treats it differently if we don't prefix this to the member element and its implicit as its the only variable available with that name ?2016-05-29 10:18:38

Ans. It makes no difference whether we add this to the variable or not. The only use of this is in the cases where there are multiple variables with the same name and we want to distinguish between the member variable and local variable. In case this is not added ,this is automatically added by the compiler in the byte code.

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

   Like      Discuss      Correct / Improve     this keyword  member elements  member variables


Frequently asked in high end product companies. Frequently asked in Deloitte.
  Q16. How is Hashmap internally implemented in Java ?Core Java2016-12-06 08:49:37

Ans. https://www.quora.com/How-is-Hashmap-in-Java-implemented-internally-What-are-the-pros-and-cons-to-use-it-What-are-the-complexities-it-provides-for-insert-delete-and-lookup/answer/Anshudeep-Bajpai?srid=iwnK

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

   Like      Discuss      Correct / Improve     hashmap  collections  hashmap internal implementation     Veritas  Sophos  Salesforce  United Health Group (UHG)  Priceline.com  Roposo  virtusa polaris  Tata Consultancy (TCS)  Hexaware Technologies  Shiksha Infotech   Synechron  Anand Rathi  Virtusa   CenturyLink  Kasmo Cloud Solutions  Dark Horse  Deloitte  conduent      expert        frequent


 Q17. Have you ever tried mocking static methods ?Testing2016-12-07 16:13:30

Ans. Yes, that can be done using Power Mock. Mockito doesnt provide a way to mock static methods.

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

   Like      Discuss      Correct / Improve     Mockito  junit  powermock     Fifth Third Bank


  Q18. What is the difference between authentication and authorization ?Authentication2017-01-23 12:56:23

Ans. Authentication is the process of verifying the identity and credentials of the user to authenticate him into the system.

whereas

Authorization is the process by which access to a segment , method or resource is determined.

Authorization is usually a step next to authentication.

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

   Like      Discuss      Correct / Improve     authentication  authorization  authentication vs authorization     ThinkBridge  Avanade  Resin.io  Worldwide Express  HCL Technologies  Tata Consultancy (TCS)  Accenture  Accenture India  Cognizant (CTS)      basic        frequent


 Q19. What is a Webdriver ?Testing2017-02-02 08:25:41

Ans. Selenium WebDriver is a tool for automating web application testing.It helps in replicating the manual tester behavior like keyboard entry, mouse events etc and then matching the output against the expected.

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

   Like      Discuss      Correct / Improve     selenium  webdriver     Global Software Resources  FICO Software  Walt Disney  Softcrylic  Sky  23andMe  Endurance Group  CitiusTech  Hitachi Consulting  Crest Premedia  LivingSocial  TEKSystems  Jabong.com  Think Future Technologies  Dollar Shave Club  Zendesk  Five9  Aptify  Symphony Teleca  Collabera  Xpanxion  Fourth Technologies  Freedom Financial  Aurigo Software Technologies  Forte Group  Wipro  Infosys  Pearson  Overstock  Elsevier  Capgemini  Cognizant (CTS)  Tech Mahindra  OLA Software  Mphasis  GrayLocus  Bhavna



Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here



 Q20. Can we have a sub enum within an enum ?Core Java2017-08-15 14:03:15

Ans. Yes

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

   Like      Discuss      Correct / Improve     enum  enum within enum


 Q21. What measures would you take to avoid Java threading issues in a multi-threaded environment ?2019-02-03 17:41:05

 This question was recently asked at 'Fifth Third Bank'.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          Fifth Third Bank


 Q22. What will be the output of following code ?

public class BuggyBread {

   private int x;

   private BuggyBread(int x){
      x = x;
   };

   public static void main(String[] args){
      BuggyBread buggybread = new BuggyBread(5);
      System.out.println(buggybread.x);
   }
}
Core Java
a. compilation error
b. undefined
c. 0
d. 5

Ans.c. 0

 Q23. What is the problem with this code ?

public class Car extends Vehicle{   
   int x;
   
   Car(int y){
      x = 5;
   }
   
   Car(){
      this(5);
      super();
   }
}
Core Java
a. We cannot overload constructors
b. Constructors should have type
c. we should have called super() before this(5)
d. We cannot have both super() and this() in a constructor

Ans.d. We cannot have both super() and this() in a constructor

 Q24. What is the problem with this code ?

public class Car extends Vehicle{
   int x;

   Car(int y){
      x = 5;
   }

   Car(){
      super();
      this.x = 5;
   }
}
Core Java
a. We cannot overload constructors
b. We cannot call super in overloaded constructor
c. we cannot have this and super in constructor
d. There is no problem

Ans.d. There is no problem



Subscribe to Java News and Posts. Get latest updates and posts on Java from Buggybread.com
Enter your email address:
Delivered by FeedBurner



comments powered by Disqus
 

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

Any input from you will be highly appreciated and It will unlock the application for 10 more requests.

Company Name:
Questions Asked:
         

X Close this