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

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Very Frequently asked to fresh graduates and less experienced. Favorite question in Walk in drives. Frequently asked in Indian Services companies.

Q11. Difference between Overloading and Overriding ?

Core Java

Ans. Overloading - Similar Signature but different definition , like function overloading.

Overriding - Overriding the Definition of base class in the derived class.

Sample Code for overloading

Sample Code for overriding

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Very frequently asked.Usually among first few questions.

Q12. What is MVC ?

Design

Ans. MVC is a Design Pattern that facilititates loose coupling by segregating responsibilities in a Web application

1. Controller receives the requests and handles overall control of the request
2. Model holds majority of the Business logic, and
3. View comprise of the view objects and GUI component

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Frequently asked to fresh graduates.

Q13. What is a Deadlock ?

Operating System

Ans. When two threads are waiting each other and cant precede the program is said to be deadlock.

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Q14. Difference between Vector and ArrayList ?

Core Java

Ans. Vectors are synchronized whereas Array lists are not.

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Q15. What is HTTP ?

Java EE

Ans. HTTP or Hypertext Transfer Protocol is internet protocol for tranmission of hypertext ( text with meta data ) over internet.

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Very frequently asked. Usually asked with questions related to String. Frequently asked at CTS / Cognizant

Q16. What is an Immutable Object ?

Core Java

Ans. Object that can't be changed after instantiation.

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Q17. What bean scopes does Spring support? Explain them.

Spring

Ans. The Spring Framework supports following five scopes -

Singleton
prototype
request
session
global-session

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Very frequently asked in HCL Tech ( Based of 4 inputs )

Q18. Write a program to reverse a string iteratively and recursively ?

Core Java

Ans. Using String method -

new StringBuffer(str).reverse().toString();

Iterative -

public static String getReverseString(String str){
StringBuffer strBuffer = new StringBuffer(str.length);
for(int counter=str.length -1 ; counter>=0;counter--){
strBuffer.append(str.charAt(counter));
}
return strBuffer;
}

Recursive -

public static String getReverseString(String str){
if(str.length <= 1){
return str;
}
return (getReverseString(str.subString(1)) + str.charAt(0);
}

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

Q19. 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

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Q20. Difference between Stack and Heap memory ?

Core Java

Ans. Stack memory areas is used to hold method and local variables while objects are always allocated memory in the heap. The heap memory is shared between multiple threads whereas Stack memory isn't.

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Q21. 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.

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Q22. What are design situations to use Singleton and Prototype Design Pattern ?

Design

Ans. Both are creational design patterns.

Singleton is used when we would like to reuse an object if object is not supposed to hold request or thread specific information. Inversely Prototype is used in situations where we would like to reuse the object information but the request / thread may require it own data to be persisted.

In short, Singleton is used in situations where we can live with single object being shared across multiple requests or threads whereas Prototype is used when we need duplicate copies of objects.

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Very Frequently asked to Senior Software Engineers or Developers.

Q23. Describe some of the Design Patterns you have used ?

Design

Ans. [Open Ended Answer]

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Q24. 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.

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Q25. What is the difference between keywords, identifiers and literals in java ?

Core Java

Ans. Keywords are the reserved words that have a pre defined meaning for the compiler and hence are restricted to be used as identifiers.

Identifiers are the name assigned to different programming constructs like classes, interfaces, methods , variables etc.

Literals are the values that are assigned to Identifiers.

For example

int count = 0;

in the above statement "int" is a keyword, "count" is an identifier and "0" is a literal

Sample Code for keywords

Sample Code for identifiers

Sample Code for literals

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Q26. What is abstraction ?

Design

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

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Q27. Explain OAuth.

Authentication

Ans. OAuth is an open-standard authorization protocol or framework that describes how unrelated servers and services can safely allow authenticated access to their assets without actually sharing the initial, related, single logon credential. Like using Google or Facebook to login to something.

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Q28. What is concurrent interface ?

Core Java

Ans. ConcurrentMap is an interface and it is a member of the Java Collections Framework. It represents a Map that is capable of handling concurrent access to it without affecting the consistency of entries in a map. ConcurrentMap interface present in java.util.concurrent package.

HashMap operations are not synchronized, while Hashtable provides synchronization. Though Hashtable is thread-safe, it is not very efficient. To solve this issue, the Java Collections Framework introduced ConcurrentMap in Java 1.5.

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Q29. What is IDE ? List few Java IDE ?

Tool

Ans. IDE stands of Integrated Development Environment. Few Java IDE's are WSAD ( Websphhere Application Developer ) , RAD ( Rational Application Developer ) , Eclipse and Netbeans.

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Q30. What are the different types of inheritance in Hibernate ?

Hibernate

Ans. Table Per Class , Table per Sub Class , Table per Concrete Class

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

Q31. Explain Singleton Design Pattern ?

Design

Ans. http://www.buggybread.com/2014/03/java-design-pattern-singleton-interview.html

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Q32. Explain the challenging problems you faced recently and how you overcame it ?

General

Ans. [Open Ended Answer]

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Q33. What is IdentityHashMap ?

Core Java

Ans. IdentityHashMap is a class that implements AbstractMap and provides a data structure with Elements having Key Value pair, just like HashMap. It is similar to HashMap except that it uses reference equality when comparing elements.

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Q34. Is it a valid identifier in Java ?

int 123Abc = 5;

Core Java

Ans. No, identifier in java cannot start with a numeral.

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Q35. What is the difference between ServletConfig and ServletContext ?

Java EE

Ans. http://www.java4s.com/java-servlet-tutorials/difference-between-servletconfig-and-servletcontext-in-java/

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Q36. What is a factory design pattern ?

Design

Ans. Factory Design Patterns is the pattern that recommends creation of separate Factory Object for creation of other object.

So its like saying - If you want to create an object of ClassA, Talk to FactoryObject ( which is an object of FactoryClass ). FactoryObject in itself encapsulates the inputs and logic required to make the decision regarding the creation and construction of object.

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Q37. What is Spring Security ?

Spring

Ans. Spring Security is a powerful and highly customizable authentication and access control framework. It is the de facto standard for securing Spring-based applications.

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Q38. Is there any relationship between Web.xml and Spring.xml ?

Spring

Ans. No, there is no relationship between web.xml and spring.xml but you have to configure spring.xml in web.xml in order initialize beans when application starts up

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Q39. Where do you see yourself in next 5 years?

General

Ans. Sample Answers -

Getting better with upcoming technologies and be a Lead developer.

In accordance with the company, working as a permenant employee.

Be an associate architect.

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Q40. Which are the most commonly used Design Patterns ?

Design

Ans. Builder ( While Writing Unit Tests )
Prototype ( Cloning )
Adapter ( asList , toString )
Chain Of Responsibility ( Logging )
Singleton
Factory ( Action Mapping )
Proxy
Observer ( Event Listener )
MVC ( Web frameworks )
Filter ( Criteria )

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