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

Interview Questions and Answers - Order By Newest

Very frequently asked. Favorite question in Walk in Drive of many Indian service companies.

Q31. What is a Final Variable ?

Core Java

Ans. Final variable is a variable constant that cannot be changed after initialization.

Sample Code for final variable

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

_{Like Discuss Correct / Improve oops java final final variable basic interview question Asked in 12 Companies basic frequent}

Try 1 Question(s) Test

Q32. What is the use of Transient Keyword ?

Core Java

Ans. It in Java is used to indicate that a field should not be serialized.

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

_{Like Discuss Correct / Improve java oops serialization transient java keywords Asked in 39 Companies intermediate frequent}

Try 2 Question(s) Test

Very Frequently asked. Usually asked along with String Class related questions.

Q33. What is an immutable class ?

Core Java

Ans. Class using which only immutable (objects that cannot be changed after initialization) objects can be created.

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

_{Like Discuss Correct / Improve java oops immutable immutability immutable immutability class string class basic interview question Asked in 18 Companies Basic frequent}

Try 2 Question(s) Test

Very frequently asked in phone and walk in interviews.

Q34. What are Marker Interfaces ? Name few Java marker interfaces ?

Core Java

Ans. An interface without any method declaration is called as marker interface. there are 3 in-built interfaces in JVM i.e. serializable, clonable, remote

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

_{Like Discuss Correct / Improve java oops interfaces marker interface serializable clonable Asked in 21 Companies intermediate frequent}

Try 1 Question(s) Test

Very frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations.

Q35. Difference between StringBuffer and StringBuilder ?

Core Java

Ans. StringBuffer is synchronized whereas StringBuilder is not.

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

_{Like Discuss Correct / Improve java string stringbuffer string class stringbuilder synchronized basic interview question infosys technologies Asked in 17 Companies basic frequent}

Try 1 Question(s) Test

Q36. What is reflection ?

Ans. It is the process of examining / modifying the behaviour of an object at runtime.

Sample Code for reflection

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

_{Like Discuss Correct / Improve java reflection reflection api ebay mindtree Asked in 29 Companies basic frequent}

Q37. What is Generalization and Specialization in terms of casting ?

Core Java

Ans. Generalization or UpCasting is a phenomenon where a sub class is prompted to a super class, and hence becomes more general. Generalization needs widening or up-casting. Specialization or DownCasting is a phenomenon where a super class is narrowed down to a sub class. Specialization needs narrowing or down-casting.

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

_{Like Discuss Correct / Improve java data types casting type casting up casting type casting downcasting type casting generalization specialization Asked in 2 Companies}

Very Frequently asked.

Q38. Explain throw, throws , try and catch in Java ?

Core Java

Ans. throw is used to re throw an exception.throws is used to declare that the method throws the respective exceptions.try block is used to identify if the respective block has thrown any exception.catch is used to catch the exception that has been thrown by the respective try block.

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

_{Like Discuss Correct / Improve java exception handling throw throws try catch Asked in 5 Companies basic frequent}

Usually asked to entry level software developers.

Q39. Write a program to swap two variables without using third

Core Java

Ans. public static void main(String[] args) {
   int num1 = 1;
   int num2 = 2;
   num1 = num1^num2;
   num2 = num1^num2;
   num1 = num1^num2;
   System.out.print("num1 = " + num1 +", num2 = "+num2);
}

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

_{Like Discuss Correct / Improve code coding Asked in 37 Companies basic frequent}

Q40. If an Abstract class has only abstract methods, What's the difference between such a class and an interface ?

Core Java

Ans. Such a class still can have member elements which can be inherited and hence facilitate code reuse. Moreover Abstract class can have non final static elements whereas interfaces are only allowed to have static final elements.

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

_{Like Discuss Correct / Improve abstract class interfaces Asked in 2 Companies Basic}

Q41. What are the problems one could face while working with serverless technologies like AWS Lambda ?

Amazon Web Services (AWS)

Ans. Warm up time for certain technologies like Java ( JVM Warmup )

Performance

Size of Deployable ( Bigger size packaging should go in S3 )

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

_{Like Discuss Correct / Improve serverless technologies aws lambda aws serverless computing amazon cloud serverless computing amazon lambda Asked in 1 Companies}

Very Frequently asked.Favorite question in Walk in drive for many Indian service companies.

Q42. What is a Final Class ?

Ans. A Class that cannot be sub classed.

Sample Code for final class

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

_{Like Discuss Correct / Improve java oops final final class java keyword basic interview question Asked in 3 Companies basic frequent}

Q43. What is a Static import ?

Core Java

Ans. By static import , we can access the static members of a class directly without prefixing it with the class name.

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

_{Like Discuss Correct / Improve java java5 static import static java keyword static import Asked in 4 Companies basic frequent}

Q44. Advantage of Collection classes over Arrays ?

Core Java

Ans. Collections are re-sizable in nature. We can increase or decrease the size as per recruitment.
Collections can hold both homogeneous and heterogeneous data's.
Every collection follows some standard data structures.
Collection provides many useful built in methods for traversing,sorting and search.

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

_{Like Discuss Correct / Improve java collections collections classes advantages of collections over arrays collections vs arrays basic interview question Asked in 6 Companies basic frequent}

Very frequently asked Hibernate interview question. Frequently asked in TCS ( based on 2 feedback )

Q45. What are different types of associations in Hibernate ?

Hibernate

Ans. There are 4 types of associations in Hibernate

One to One
One to Many
Many to One
Many to Many

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

_{Like Discuss Correct / Improve hibernate associations Asked in 11 Companies frequent}

Very frequently asked if being interviewed for hibernate. Frequently asked in Tata Consultancy (TCS) and Overstock.com

Q46. Difference between load and get ?

Hibernate

Ans. If id doesnt exist in the DB load throws an exception whereas get returns null in that case.get makes the call to DB immediately whereas load makes the call to proxy.

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

_{Like Discuss Correct / Improve hibernate Asked in 16 Companies basic frequent}

Q47. What are some different logging levels for log4j ?

Log4j

Ans. DEBUG
ERROR
ALL
WARN
INFO
FATAL
OFF
TRACE
TRACE_INT
WARN

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

_{Like Discuss Correct / Improve java log4j log4j level logging error logging Asked in 10 Companies}

Q48. How are values passed in Java ? By value or reference ?

Core Java

Ans. Java only provides pass by value.

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

_{Like Discuss Correct / Improve ebay pass by value pass by reference method call methods functions function call Asked in 10 Companies basic frequent}

Q49. What was the driving force to introduce default methods in Interfaces wef from Java 8 ?

Core Java

Ans. Earlier any class implementing an interface was supposed to implement all methods declared in an interface. There was no place for optionally implementing all or subset of methods.Though we have abstract classes wherein we could have provided such a mechanism by declaring some methods as abstract while providing definition for some. But as Abstract classes have a body and are comparatively heavier than interfaces and interfaces associate closely to the concept of providing interfacing than abstract classes, Java might have though of providing optional implementation for default methods. This way same interface can be reused in variety of ways rather than making copies of an interface to suit different needs.

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

_{Like Discuss Correct / Improve java 8 java8 interface default methods default methods Asked in 6 Companies}

Very Frequently asked to Senior Software Engineers or Developers.

Q50. Describe some of the Design Patterns you have used ?

Design

Ans. [Open Ended Answer]

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

_{Like Discuss Correct / Improve design patterns Asked in 17 Companies intermediate frequent}

Q51. What is the difference between authentication and authorization ?

Authentication

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 Asked in 9 Companies basic frequent}

Q52. What is abstraction ?

Design

Ans. Abstraction is a process of hiding the implementation details and describing only the functionality to the user.

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

_{Like Discuss Correct / Improve bstraction oops concepts oops principle Asked in 22 Companies}

Q53. What is a cookie ?

Java EE

Ans. A cookie is a small piece of text stored on a user's computer by the browser for a specific domain. Commonly used for authentication, storing site preferences, and server session identification.

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

_{Like Discuss Correct / Improve cookie javascript web application session management browser j2ee Asked in 16 Companies basic frequent}

Frequently asked.

Q54. What is an Iterator?

Core Java

Ans. Iterator is an interface that provides methods to iterate over any Collection.

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

_{Like Discuss Correct / Improve java collections iterator Asked in 11 Companies basic frequent}

Q55. What are transient variables in java?

Core Java

Ans. Transient variables are variable that cannot be serialized.

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

_{Like Discuss Correct / Improve java serialization transient Asked in 15 Companies intermediate rare}

Q56. What is a cloneable interface and what all methods does it contain?

Core Java

Ans. Cloneable is a declaration that the class implementing it allows cloning or bitwise copy of it's object state. It is not having any method because it is a MARKER interface.

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

_{Like Discuss Correct / Improve java oops cloneable marker interface cloning Asked in 2 Companies}

Q57. What is the use of HashCode in objects ?

Core Java

Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc.

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

_{Like Discuss Correct / Improve java string hashcode hash code string comparison hashtable Asked in 17 Companies basic frequent}

Very Frequently asked. Favorite question in walkins and telephonic interviews. Usually among first few questions. Asked in different variants. Must know for intermediate and expert professionals.Among Top 10 frequently asked questions.

Q58. What is rule regarding overriding equals and hashCode method ?

Core Java

Ans. A Class must override the hashCode method if its overriding the equals method.

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

_{Like Discuss Correct / Improve java collections hashcode hash code equals collections Asked in 44 Companies intermediate frequent}

Try 1 Question(s) Test

Very frequently asked. Usually followed by questions related to private constructor and synchronized access. Frequently asked in JPMorgan and TCS (Based on 2 feedback)

Q59. Explain Singleton Design Pattern ?

Design

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 Asked in 46 Companies intermediate frequent}

Q60. Can we have foreign key reference to a non primary key column ?

Database

Ans. Yes, but the respective key in the foreign table should be declared Unique.

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

_{Like Discuss Correct / Improve sql database oracle Asked in 2 Companies}

Search Interview Questions

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