Advance & Core Java Interview Question and Answers | Search Java Coding Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com
Share

Search Interview Questions


 3167 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

   



Java - Interview Questions and Answers - Order By Newest

   next 40
 Q41. What is session tracking and how do you track a user session in servlets?Java EE
Admin
info@buggybread.com
Ans. Session tracking is a mechanism that servlets use to maintain state about a series requests from the same user across some period of time. The methods used for session tracking are:

User Authentication - occurs when a web server restricts access to some of its resources to only those clients that log in using a recognized username and password

Hidden form fields - fields are added to an HTML form that are not displayed in the client's browser. When the form containing the fields is submitted, the fields are sent back to the server

URL rewriting - every URL that the user clicks on is dynamically modified or rewritten to include extra information. The extra information can be in the form of extra path information, added parameters or some custom, server-specific URL change.

Cookies - a bit of information that is sent by a web server to a browser and which can later be read back from that browser.

HttpSession- places a limit on the number of sessions that can exist in memory.

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

   Like      Discuss      Correct / Improve     j2ee   servlets   session   session management   web applications   cookies   httpsession   url rewriting   architecture     Infosys

Advanced level question usually asked to senior developers , leads and architects.
 Q42. How does volatile affect code optimization by compiler?Core Java
Admin
info@buggybread.com
Ans. Volatile is an instruction that the variables can be accessed by multiple threads and hence shouldn't be cached. As volatile variables are never cached and hence their retrieval cannot be optimized.

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

   Like      Discuss      Correct / Improve     java   java keywords   volatile   synchronization   compiler optimization   variable caching   architecture     Embedded security  Driver engineer  Sokrati      expert

 Q43. Difference between Static and Singleton Class ?Core Java2016-11-30 21:00:43

Ans. 1. Static class is a class which cannot be instantiated and all its members are static whereas Singleton is the class that only permit creation of single object and then the object is reused.

2. As there is no object in Static class, it cannot participate in runtime Polymorphism.

3. As Static class doesnt allow creating objects and hence it cannot be serialized.

4. Static class body is initialized eagerly at application load time whereas Singleton object can be initiated eagerly using static blocks or lazily on first need.

5. Its not recommended to use pure static class as it fails to use many OOPs concepts.

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

   Like      Discuss      Correct / Improve     Static Class  Singleton  Static Class vs Singleton     Netflix  EPAM  Ebay      Intermediate        frequent

Advanced level question frequently asked in US based companies. Recently asked in EMC and Intuit.
  Q44. Can you provide some implementation of a Dictionary having large number of words ? Solution
Admin
info@buggybread.com
Ans. Simplest implementation we can have is a List wherein we can place ordered words and hence can perform Binary Search.

Other implementation with better search performance is to use HashMap with key as first character of the word and value as a LinkedList.

Further level up, we can have linked Hashmaps like ,

hashmap {
a ( key ) -> hashmap (key-aa , value (hashmap(key-aaa,value)
b ( key ) -> hashmap (key-ba , value (hashmap(key-baa,value)
....................................................................................
z( key ) -> hashmap (key-za , value (hashmap(key-zaa,value)
}

upto n levels ( where n is the average size of the word in dictionary.

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

   Like      Discuss      Correct / Improve     java   collections   hashmap   binary search   search algorithm   advanced   architecture   data structure     Dell EMC   Intuit   Corporate Brokers  PWC India  Yahoo  Oracle        frequent
Try 1 Question(s) Test

Not frequently asked as it was introduced with Java 8.
 Q45. Difference between final and effectively final ? Why is effectively final even required ?Core Java
Admin
info@buggybread.com
Ans. Final variable means a variable that has been declared final and hence cannot be de referenced after initialization. Effective final means a variable that has not been declared final but haven't been reassigned the value after initialization.

First is the regulation that restricts the reassignment and will raise a compilation error if we try to do so. Second is the outcome without the restriction.

Effective Final is the eventual treatment of the variable that is required for many features. For eq - Java 8 requires that local variables referenced from a lambda expression must be final or effectively final.It means all local referenced from lambda expressions must be such that their value shouldn't be changed after initialization whether declared final or not.

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


   Like      Discuss      Correct / Improve     java   java8   java 8   final   effective final   final vs effective final   lambda expressions      expert
Try 2 Question(s) Test

Frequently asked to fresh graduates and less experienced.
 Q46. Why do we write public static void main ? Can we use some other syntax too for main ?Core Java
Admin
info@buggybread.com
Ans. 1. public is the access modifier that makes the method accessible from anywhere, static is the keyword that makes it accessible even without creating any object, void means it doesn't return anything , String args[] is the array of argument that the method receives.

2. If we use main without the string args , it will compile correctly as Java will treat it as just another method. It wont be the method "main" which Java looks for when it looks to execute the class and hence will throw

Error: Main method not found in class , please define the main method as:
public static void main(String[] args)

3. Main is not a keyword but a special string that Java looks for while initiating the main thread.

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


   Like      Discuss      Correct / Improve     java   main method     Cognizant (CTS)  Computer Solutions & Software International (CSSI)  Telcoinabox  IBM Pune      basic        frequent
Try 1 Question(s) Test

 Q47. What are the advantages and disadvantages of static variables and static methods ?Core Java
Admin
info@buggybread.com
Ans. Advantages

Can do meta object operations ( like validating something before creating objects , keep count of number of objects )

Can do operations which have nothing to do with objects but still you want them to be tied to Class.

Disadvantages

Commonly used to static variables sometime leads to problems due to access by different objects.

Are not tied to objects so doesn't reflect pure Object Oriented approach.

Needs to be synchronized so as to avoid update conflicts by mutiple objects and threads.

Some limitation in testing as not all frameworks have facility to mock them. Powermock has but Mockito doesnt

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

   Like      Discuss      Correct / Improve     java   static   static variables   static methods

Very Frequently asked. Have been asked in HCL Technologies very frequently ( based on 3 feedback ). Among first few questions in many interviews.
  Q48. 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

 Q49. Which keyword is used to provide explicit access of a code block to single thread ?

a. Transient
b. Final
c. Explicit
d. Synchronized		Core Java
Anonymous
Ans. Synchronized

  Sample Code for Synchronized

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

   Like      Discuss      Correct / Improve     java   threads   multithreading     Infoview  HCL Technologies      basic


Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here


 Q50. Can you give a real world example of Encapsulation and Abstraction ?Core Java2016-05-29 13:47:31

Ans. Car Engine is an example of encapsulation and abstraction. You ignite the car using an interface called starter and least bothered about how the tire actually moves (This is abstraction). The engine encapsulates the complete process to itself only and doesn't allow you to start the other components like the radiator etc ( this is excapsulation )

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

   Like      Discuss      Correct / Improve     encapsulation  object oriented programming (oops)  oops concepts  abstraction  oops  oops features  java features     MAQ Software  Daffodil Software  Quickstart Global  Alliance Global Services  InfoStretch  Intelligrape  Prowareness  Support.com  Cognizant (CTS)  BNT SOFT  Clairvoyant TechnoSolutions  Suyati Technologies  3DPLM Software Solutions

 Q51. Can we declare static variables as transient ?Core Java2017-01-12 11:12:48

Ans. It's weird that compiler doesn't complain if we declare transient with static variable because it makes no sense. At least a warning message saying "transient is useless in this situation" would have helped with code cleaning.

Static variables are never serialized and transient is an indication that the specified variable shouldn't be serialized so its kind of double enforcement not to serialize.

It could be that as it makes no different to the variable behavior and hence using both keywords with a variable are permitted.

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

   Like      Discuss      Correct / Improve     static  transient  serialization     HCL Technologies      expert        rare
Try 1 Question(s) Test

 Q52. How is string object immutable if we can concat a string to it ?Core Java2017-08-08 09:50:28

Ans. Because it doesn't make the change in the existing string but would create a new string by concatenating the new string to previous string. So Original string won't get changed but a new string will be created. That is why when we say

str1.concat("Hello");

It means nothing because we haven't specified the reference to the new string and we have no way to access the new concatenated string. Accessing str1 with the above code will still give the original string.

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

   Like      Discuss      Correct / Improve     string  string immutable  immutability  string concat

 Q53. Difference between JVM, JRE and JDK ?Core Java2017-10-31 08:36:22

Ans. JDK(Java Development kit) = Development Kit comprising of JVM , library and development tools for developers

JRE (Java Run time Environment) - Comprise of JVM and set of libraries

JVM(Java Virtual Machine) = Interpreter which reads the .class file line by line.

When we install JDK, JRE also get installed so we can write,compile and excute our code. Used by developer. Without JDK we can only execute the program using JRE.

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

   Like      Discuss      Correct / Improve     jvm  jre  jdk  jvm vs jre vs jdk     Infosys  HCL Technologies  Mphasis  Polaris]

Very Frequently asked across all type of companies and across all levels.
  Q54. Difference between Public, Private, Default and Protected ?Core Java
Anonymous
Ans. Private - Not accessible outside object scope.

Public - Accessible from anywhere.

Default - Accessible from anywhere within same package.

Protected - Accessible from object and the sub class objects.

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

   Like      Discuss      Correct / Improve     java   oop   access specifier   public   private   default   protected   basic interview question     HCL Technologies  Tata Consultancy (TCS)  IBM  Wipro  Deegit  Argonne National Laboratory  Motorola Mobility  Accenture  Accenture India  Deegit  Cerner      basic        frequent
Try 1 Question(s) Test

Very frequently asked. Favorite question in Walk in Drive of many Indian service companies.
  Q55. What is a final method ?Core Java
Anonymous
Ans. Its a method which cannot be overridden. Compiler throws an error if we try to override a method which has been declared final in the parent class.

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

   Like      Discuss      Correct / Improve     java   oops   final   final method     Oracle  Intertek  HCL Technologies  Tata Consultancy (TCS)  Accenture  Accenture India   IBM  Goldman Sachs   TrueCar   Intertek RedMane   Antra  Flanders Software  Causecode Technologies  ING Direct  Intertek  Tudip Technologies  Finance One  Mphasis  #i Infotech  L&T Infotech  Tata Elxsi  State Farm  Cerner  Deegit  Infosys Technologies  Wipro  Mahindra Satyam  Global Logic  InfoGain  Cognizant (CTS)      basic        frequent
Try 1 Question(s) Test

 Q56. What will this code print ?

String a = new String ("TEST");
String b = new String ("TEST");
if(a == b) {
System.out.println ("TRUE");
} else {
System.out.println ("FALSE");
}		Core Java
Anonymous
Ans. FALSE. == operator compares object references, a and b are references to two different objects, hence the FALSE. .equals method is used to compare string object content.

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

   Like      Discuss      Correct / Improve     string   string class   java   ==   object references   coding     Capgemini  HCL Technologies      basic        frequent
Try 1 Question(s) Test

  Q57. What is casting?Core Java
Anonymous
Ans. There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference

 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   basic interview question     Mindtree  HCL Technologies  Wipro  Tata Consultancy (TCS)  Infosys  KPMG  Accenture  Accenture India      basic        frequent

Advanced level question usually asked in High end product companies. Have been asked in Google and Amazon (Based on 1 Feedback)
  Q58. Describe, in general, how java's garbage collector works ?Core Java
Anonymous
Ans. The Java runtime environment deletes objects when it determines that they are no longer being used. This process is known as garbage collection. The Java runtime environment supports a garbage collector that periodically frees the memory used by objects that are no longer needed. The Java garbage collector is a mark-sweep garbage collector that scans Java dynamic memory areas for objects, marking those that are referenced. After all possible paths to objects are investigated, those objects that are not marked (i.e. are not referenced) are known to be garbage and are collected.

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


   Like      Discuss      Correct / Improve     java   garbage collection   java memory management   advanced     LinkedIn  Infosys  Google  Netflix  Amazon  Huawei Technologies  JP Morgan  enGenius  CitiusTech  Goldman Sachs  Bank Of America India  Salesforce  Addteq  Criteo  Capgemini  Horizon Solutions  Way dot com  Mphasis  TrueCaller  Intel  Symantec      intermediate        frequent
Try 4 Question(s) Test

Very Frequently asked to fresh graduates and less experienced. Favorite question in Walk in drives. Frequently asked in Indian Services companies.
  Q59. Difference between Overloading and Overriding ?Core Java
Anonymous
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

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

   Like      Discuss      Correct / Improve     java   oops   overloading   overriding   oops concepts   basic interview question     PC Technology  Cognizant (CTS)  Donlen   hybris Software  RedMane  Allerin Technologies  Gemalto  Allerin Technologies  HCL Technologies  Tata Consultancy (TCS)  Accenture  Accenture India  Infosys Technologies  Polaris  United Healthcare India  IBM India  Xchanging  American Express  Antra  Flipp  Computer Sciences Corporation (CSC)  Garmin  NetSuite  Donlen  Hudsons Bay  Techlogix  SevOne  Synactive  Oodles Technologies  FDM Group  Marlabs  RedMane Technology  Faichi Solutions  TD  Tech Mahindra  Shutterfly  Luxoft  PC Technology  CCC Information Services  State Farm  Raja Software  Mastek  EPAM  Morgan Stanley  SummitWorks  Sony  Citibank  Emtec  LowerMyBills  Consilience  Xavor  AllState  FasTrak  AmTrust Financial  Walt Disney  Ultramain Systems  International Turnkey Systems  Knoldus Software  CA Technologies  Amdocs  FDM Group  Hybris  Fidelity  United Health Group (UHG)  Bluewhale Solutions  Pegasystems  Revature   Innoplexus  Vanguard  AptSource  Perficient  Grapecity  Subex  QuintilesIMS  NimbleUser  Expeditors Associate  Sapient  HR Cloud  Summitworks  Jabong.com  Kony Labs  Price Waterhouse Coopers (PWC)      basic        frequent
Try 1 Question(s) Test


Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here


  Q60. What is Serialization ? Why do we need it ?Core Java
Anonymous
Ans. Storing the state of an object in a file or other medium is called serialization.

Classes can communicate only if they are built together ( as they need Byte code for communication ). What if we need to enable communication between different applications ( i.e they have been built independently or even they reside at different locations ), We need a mechanism that will transfer the Bean state to a Medium than can be transferred to the receiving application.

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


   Like      Discuss      Correct / Improve     java   oops   serialization     Computer Sciences Corporation (CSC) India   Tieto  Uproar  Priceline.com  HCL Technologies  Cognizant (CTS)  Hewlett Packard (HP)  Mphasis  Infosys Technologies  Global Logic  Microsoft  Raytheon  ForgeRock  WhatsApp  CricBuzz  Imagination Learning Systems  EROAD      basic        frequent
Try 1 Question(s) Test

 Q61. What are the benefits of using Spring Framework ?Spring
Admin
info@buggybread.com
Ans. Spring enables developers to develop enterprise-class applications using POJOs. The benefit of using only POJOs is that you do not need an EJB container product.

Spring is organized in a modular fashion. Even though the number of packages and classes are substantial, you have to worry only about ones you need and ignore the rest.

Spring does not reinvent the wheel instead, it truly makes use of some of the existing technologies like several ORM frameworks, logging frameworks, JEE, Quartz and JDK timers, other view technologies.

Testing an application written with Spring is simple because environment-dependent code is moved into this framework. Furthermore, by using JavaBean-style POJOs, it becomes easier to use dependency injection for injecting test data.

Spring is web framework is a well-designed web MVC framework, which provides a great alternative to web frameworks such as Struts or other over engineered or less popular web frameworks.

Spring provides a convenient API to translate technology-specific exceptions (thrown by JDBC, Hibernate, or JDO, for example) into consistent, unchecked exceptions.

Lightweight IoC containers tend to be lightweight, especially when compared to EJB containers, for example. This is beneficial for developing and deploying applications on computers with limited memory and CPU resources.

Spring provides a consistent transaction management interface that can scale down to a local transaction

  Sample Code for spring

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

   Like      Discuss      Correct / Improve     java   spring framework   mvc   spring container   architecture   technical architect   java architect   technical lead  ioc     MasterCard  Jean Martin      basic        frequent

 Q62. What things should be kept in mind while creating your own exceptions in Java?Core Java
Admin
info@buggybread.com
Ans. All exceptions must be a child of Throwable.

If you want to write a checked exception that is automatically enforced by the Handle or Declare Rule, you need to extend the Exception class.

You want to write a runtime exception, you need to extend the RuntimeException class.

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

   Like      Discuss      Correct / Improve     java   exceptions   exception handling   user defined exceptions   throwable   architecture   library development   technical architect   technical lead

 Q63. What is the difference between the following two code lines ?

1. new OuterClass().new InnerClass();

2. new OuterClass.InnerClass();		Core Java2016-06-30 14:45:37

Ans. In first case we are trying to initialize Inner class object using the instance of Outer Class whereas in second case we are trying to initialize the Inner class object directly using the Outer class name.

In second case , Inner class is "static inner class" as we cannot access "non static inner class" using Classname alone.

In first case, the inner class could be either "static inner class" or "non static inner class".

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

   Like      Discuss      Correct / Improve     inner classes  inner class   static inner class   new operator

 Q64. What are the different uses of Interfaces in Java ?Core Java2016-07-20 15:14:43

Ans. 1. Regulation / Enforcement / Policy / Contract , It's primary use

2. Use as a collection of utility methods(since java 8 through default methods)

3. Collecting constants together, As Interface are lighter, it makes sense to use them instead of classes if no getters and setters required.

4. Creation of Custom Annotations

5. Special services like marker interface

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

   Like      Discuss      Correct / Improve     interfaces   uses of interfaces in java     BMC Software

 Q65. What do you look for when you do code review ?Core Java2016-12-28 13:59:38

Ans. Modularity - First sign of good code is whether it has been segregated into methods and classes appropriately. I dont mind it in excess because I believe that is forward looking strategy as applications tends to expand and eventually become hard to read.

Self Explanatory - Variables and methods should be named in a way that the code should be self explanatory even without comments. Use of Constant variables to explain use of literal.

Proper Code Reuse - If there is anything being reused , it should be moved to parent classes / methods.

Proper composition calls - Composed hierarchy should not be access in just single line. One or two levels is ok but having multiple levels make it hard to read and debug.

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

   Like      Discuss      Correct / Improve     code review  clean code     [Sofi]      intermediate        frequent

Usually asked in relation to casting and ClassCastException.
 Q66. What is instanceOf operator ? Explain it's use ?Core Java2017-06-12 07:58:22

Ans. The operator instanceOf is used to verify if the specified object is the instance of specified class or interface.

Syntax if(x instanceOf ABC)

where x is an object reference and ABC could be a class name or interface name. The above statement will be true if x holds an object that is an instance of ABC or any of the child class of ABC or if x holds an object that implements ABC.

instanceOf operator is used to verify in case of downcasting. For ex -

DerivedClass extends BaseClass

x is the reference of BaseClass but holds DerivedClass object ( Polymorphism )

There is an operation that is defined in Derived Class, let's say derivedClassMethod()

We cannot call derivedClassMethod() directly using x as x is reference of BaseClass and not DerivedClass and hence can only access methods that are defined in BaseClass and overridden in derived class.

Though we can cast it to DerivedClass as following
((DerivedClass)x).derivedClassMethod();

But it may throw ClassCastException in case x doesn't hold an instance of DerivedClass at that point.

So before casting it to DerivedClass we may like to make sure that it is an instance of DerivedClass and hence won't throw ClassCastException.

So we make a check for it

if(x instanceOf DerivedClass) {
((DerivedClass)x).derivedClassMethod();
}

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

   Like      Discuss      Correct / Improve     instanceOf  instanceOf operator  Why we need instanceOf operator  use of instanceOf operator     Trimax IT Infrastructure & Services   ultramain      Intermediate        frequent

 Q67. Let's suppose we have an to destroy objects, Design a program to implement garbage collection ?Design2017-08-04 14:08:01

Ans. Step 1 - We can create a Registry Class having Map of all created objects as key and References list as value.

Step 2 - Whenever we create an object , we should update the Registry in the constructor to add the new object.

Step 3 - Whenever we assign a new reference to the object , we need to update the entry in Map. Similarly if the reference get's removed ( end of scope etc ), we need to remove the entry of reference from the list.

Step 4 - We can have threaded code to monitor the Map to see if any object looses all it's references and should call the method to destroy object and clean the memory.

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

   Like      Discuss      Correct / Improve     garbage collection

Frequently asked to fresh graduates and less experienced developers.
 Q68. Explain multithreading in Java ?Core Java
Anonymous
Ans. 1. Multithreading provides better interaction with the user by distribution of task

2. Threads in Java appear to run concurrently, so it provides simulation for simultaneous activities.The processor runs each thread for a short time and switches among the threads to simulate sim-ultaneous execution (context-switching) and it make appears that each thread has its own processor.By using this feature, users can make it appear as if multiple tasks are occurring simultaneously when, in fact, each is running for only a brief time before the context is switched to the next thread.

3. We can do other things while waiting for slow I/O operations.In the java.iopackage, the class InputStreamhas a method, read(), that blocks until a byte is read from the stream or until an IOExceptionis thrown. The thread that executes this method cannot do anything elsewhile awaiting the arrival of another byte on the stream.

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

   Like      Discuss      Correct / Improve     java   threads   multi threading  concurrency   multithreading     Hamsini ECommerce   Cognizant (CTS)  Cumulus Systems  Cognizant (CTS)      intermediate        frequent
Try 1 Question(s) Test

 Q69. What is JDBC? Describe the steps needed to execute a SQL query using JDBC.Database
Anonymous
Ans. The JDBC is a pure Java API used to execute SQL statements. It provides a set of classes and interfaces that can be used by developers to write database applications.

The steps needed to execute a SQL query using JDBC:

1. Open a connection to the database.
2. Execute a SQL statement.
3. Process th results.
4. Close the connection to the database.

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

   Like      Discuss      Correct / Improve     java   jdbc   db connectivity     Nucleus Software Exports  Caprus IT      basic        frequent


Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here


 Q70. Can we access instance variables within static methods ?Core Java
Anonymous
Ans. Yes.we cannot access them directly but we can access them using object reference.Static methods belong to a class and not objects whereas non static members are tied to an instance. Accessing instance variables without the instance handler would mean an ambiguity regarding which instance the method is referring to and hence its prohibited.

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

   Like      Discuss      Correct / Improve     java   oops   static   static methods   java keywords     Oracle

 Q71. Difference between C++ and Java ?Core Java
Admin
info@buggybread.com
Ans. Java does not support pointers.

Java does not support multiple inheritances.

Java does not support destructors but rather adds a finalize() method. Finalize methods are invoked by the garbage collector prior to reclaiming the memory occupied by the object, which has the finalize() method.

Java does not include structures or unions because the traditional data structures are implemented as an object oriented framework.

C++ compiles to machine language , when Java compiles to byte code .

In C++ the programmer needs to worry about freeing the allocated memory , where in Java the Garbage Collector takes care of the the unneeded / unused variables.

Java is platform independent language but c++ is depends upon operating system.

Java uses compiler and interpreter both and in c++ their is only compiler.

C++ supports operator overloading whereas Java doesn't.

Internet support is built-in Java but not in C++. However c++ has support for socket programming which can be used.

Java does not support header file, include library files just like C++ .Java use import to include different Classes and methods.

There is no goto statement in Java.

There is no scope resolution operator :: in Java. It has . using which we can qualify classes with the namespace they came from.

Java is pass by value whereas C++ is both pass by value and pass by reference.

Java Enums are objects instead of int values in C++

C++ programs runs as native executable machine code for the target and hence more near to hardware whereas Java program runs in a virtual machine.

C++ was designed mainly for systems programming, extending the C programming language whereas Java was created initially to support network computing.

C++ allows low-level addressing of data. You can manipulate machine addresses to look at anything you want. Java access is controlled.

C++ has several addressing operators . * & -> where Java has only one: the .

We can create our own package in Java(set of classes) but not in c and c++.

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

   Like      Discuss      Correct / Improve     java   c++   difference between java and c++   programming concepts   programming languages   architecture   technical architect   technical lead     Intuit

  Q72. Difference between SAX and DOM Parser ?Xml
Admin
info@buggybread.com
Ans. A DOM (Document Object Model) parser creates a tree structure in memory from an input document whereas A SAX (Simple API for XML) parser does not create any internal structure.

A SAX parser serves the client application always only with pieces of the document at any given time whereas A DOM parser always serves the client application with the entire document no matter how much is actually needed by the client.

A SAX parser, however, is much more space efficient in case of a big input document whereas DOM parser is rich in functionality.

Use a DOM Parser if you need to refer to different document areas before giving back the information. Use SAX is you just need unrelated nuclear information from different areas.

Xerces, Crimson are SAX Parsers whereas XercesDOM, SunDOM, OracleDOM are DOM parsers.

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

   Like      Discuss      Correct / Improve     java   xml   parsers   sax   dom parser   difference   architecture   technical lead   technical architect  markup language      First Advantage  Wellington Management  Chase Reference Data Distribution  System Soft Technologies  TD Bank Canada  JPMorgan Chase  Tata Consultancy (TCS)  PayPal  Citibank  Free Doctor Helpline  Wells Fargo  Huawei Technologies   HealthFirst  American Express        frequent
Try 1 Question(s) Test

 Q73. What is a stream and what are the types of Streams and classes of the Streams?Core Java
Admin
info@buggybread.com
Ans. A Stream is an abstraction that either produces or consumes information. There are two types of Streams :

Byte Streams: Provide a convenient means for handling input and output of bytes.

Character Streams: Provide a convenient means for handling input & output of characters.

Byte Streams classes: Are defined by using two abstract classes, namely InputStream and OutputStream.

Character Streams classes: Are defined by using two abstract classes, namely Reader and Writer.

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

   Like      Discuss      Correct / Improve     java   file io   streams   byte stream   character stream  file handling

Frequently asked to fresh graduates and less experienced.
 Q74. Difference between Composition and Inheritance ?Core Java
Admin
info@buggybread.com
Ans. Inheritance means a object inheriting reusable properties of the base class. Compositions means that an abject holds other objects.

In Inheritance there is only one object in memory ( derived object ) whereas in Composition , parent object holds references of all composed objects.

From Design perspective - Inheritance is "is a" relationship among objects whereas Composition is "has a" relationship among objects.

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


   Like      Discuss      Correct / Improve     java   oops   oops concepts   inheritance  object oriented programming (oops)  oops concepts   composition  object oriented programming (oops)  oops concepts   difference between   basic interview question      basic        frequent
Try 2 Question(s) Test

Frequently asked to experienced developers. Recently asked in many US interviews.
  Q75. What is database deadlock ? How can we avoid them?Database
Admin
info@buggybread.com
Ans. When multiple external resources are trying to access the DB locks and runs into cyclic wait, it may makes the DB unresponsive.

Deadlock can be avoided using variety of measures, Few listed below -

Can make a queue wherein we can verify and order the request to DB.

Less use of cursors as they lock the tables for long time.

Keeping the transaction smaller.

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


   Like      Discuss      Correct / Improve     java   database   architecture     MSCI  Vudu  Bank Of America  Sears  BlueCoat  Symantec      expert        frequent

 Q76. What will be the output of following code ?

public static void main(String[] args){
String name = null;
File file = new File("/folder", name);
System.out.print(file.exists());
}		Core Java
Admin
info@buggybread.com
Ans. NullPointerException

at line: "File file = new File("/folder", name);"

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

   Like      Discuss      Correct / Improve     java   io   file   fileio   coding   code   file handling

 Q77. Difference between Predicate, Supplier and Consumer ? Core Java
Admin
info@buggybread.com
Ans. Predicate represents an anonymous function that accepts one argument and produces a result.

Supplier represents an anonymous function that accepts no argument and produces a result.

Consumer represents an anonymous function that accepts an argument and produces no result.

  Sample Code for Predicate

  Sample Code for Supplier

  Sample Code for Consumer

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

   Like      Discuss      Correct / Improve     java   java8   predicate   consumer   supplier   lambda expression      expert

Not frequently asked as it was introduced with Java 8.
 Q78. What is StringJoiner ?Core Java
Admin
info@buggybread.com
Ans. StringJoiner is a util method to construct a string with desired delimiter. This has been introduced with wef from Java 8.

Sample Code

StringJoiner strJoiner = new StringJoiner(".");

strJoiner.add("Buggy").add("Bread");

System.out.println(strJoiner); // prints Buggy.Bread


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

   Like      Discuss      Correct / Improve     java   java8   java 8   string   stringjoiner

 Q79. Which of the following can be marked static ?

a. Methods , Variables and Initialization Blocks.
b. Methods , Variables , Initialization Blocks and Outer Classes and nested Classes.
c. Methods , Variables , Initialization Blocks and Outer Classes.
d. Methods , Variables , Initialization Blocks and nested Classes		Core Java
Anonymous
Ans. Methods , Variables , Initialization Blocks and nested Classes

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

   Like      Discuss      Correct / Improve     oops   java   static   nested classes   static nested classes
Try 2 Question(s) Test


Do you think these are the Best Java Frameworks ?

OpenXavaSPRING MVCApache StripesCheck everything
that is Best in Java

Click Here


 Q80. Collections.sort can only be performed on ..

a. Set
b. List
c. Map
d. Any Collection implementation		Core Java
Anonymous
Ans. List

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

   Like      Discuss      Correct / Improve     collections   java   sorting
Try 2 Question(s) Test

previous 40   next 40

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

X Close this

Help Us Improve.
Please share your
interview experience.

Company Name:   


Questions Asked: