Interview Questions and Answers for 'At' | Search Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com

Search Interview Questions


 More than 3000 questions in repository.
 There are more than 900 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 - Order By Rating

   next 30
 Q571. Can we declare static variables as transient ?Core Java
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     Asked in 1 Companies      expert        rare
Try 1 Question(s) Test

 Q572. Which elements of a class are ignored during serialization ?Core Java
Ans. 1. Objects are serialized and not classes and hence Static variables are ignored.

2. Transient is an explicit declaration to ignore the variable during serialization and hence transient instance variables are ignored too.

3. Base class instance variables if the base class hasn't been declared serializable.

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

   Like         Discuss         Correct / Improve     serialization     Asked in 1 Companies      intermediate        frequent
Try 1 Question(s) Test

 Q573. Which environment variables do we need to set in order to run Java programs?Core Java
Ans. PATH, CLASSPATH and JAVA_HOME

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

   Like         Discuss         Correct / Improve     environment variables  path  classpath  java_home     Asked in 3 Companies      basic        frequent

 Q574. Scale yourself on Java on the scale of 1 to 10General
Ans. [Open Ended Answer]

The objective of the question is to check how efficient one is in the language so that appropriate level questions are asked. Don't tell too high number if you are being interviewed for a junior or mid level position as the interviewer may throw advance level questions.

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

   Like         Discuss         Correct / Improve          Asked in 17 Companies

 Q575. 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

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

   Like         Discuss         Correct / Improve     spring  web.xml  spring.xml  deployment descriptor     Asked in 1 Companies

 Q576. Will finally run if we have return statement and it exits the method early ?Core Java
Ans. finally will execute in all graceful situations - graceful executions as well as graceful exceptions. The only situation when finally block won't execute is when the app is abruptly stopped, killed or unplugged.

  Sample Code for finally

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

   Like         Discuss         Correct / Improve     finally      Intermediate

Very frequently asked. Usually asked in this format or as difference with interfaces / concrete classes.
  Q577. What is an abstract class ?Core Java
Ans. Abstract class is the class that is not supposed to be instantiated. The purpose of the class to only have extension to the derived class.

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

   Like         Discuss         Correct / Improve     abstract class     Asked in 6 Companies      basic        frequent

Frequently asked in high end product companies.
 Q578. Write code for LRU CacheCore Java
Ans. https://www.geeksforgeeks.org/lru-cache-implementation/

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

   Like         Discuss         Correct / Improve     cache  LRU cache  coding  code     Asked in 10 Companies      intermediate

 Q579. Why main method is declared static ?Core Java
Ans. static is the keyword that makes it accessible even without creating any object and using class name only. Making it non static would like creation of object upfront before calling the method.

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

   Like         Discuss         Correct / Improve     main method  static     Asked in 4 Companies      Basic

 Q580. What is the use of static keyword in Java ?Core Java
Ans. static keyword is used to specify that the respective programming construct ( method , variable ) belongs to the class and not to its instance and is supposed to be shared by all instances of the class.

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

   Like         Discuss         Correct / Improve     static keyword     Asked in 1 Companies      basic        frequent

 Q581. 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.

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

   Like         Discuss         Correct / Improve     design pattern  factory design pattern     Asked in 9 Companies

Frequently asked in Cognizant ( Based on 2 feedback )
  Q582. What are Inner , Outer , Left and Right Joins in SQL ?Database
Ans. Inner join is the intersection of two tables on the condition defined by the where clause i.e will get records from both tables matched by a column.

Outer join is the union of two tables i.e will get all records from both tables and will put null in the columns where related records are not present.

Left Outer join is the left union of two tables i.e all records from the table on the left and values from the right table for related records else null for the columns from right table.

Right Outer join is the right union of two tables i.e all records from the table on the right and values from the left table for related records else null for the columns from left table.

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

   Like         Discuss         Correct / Improve     sql  inner join  outer join  right join  left join     Asked in 24 Companies      basic        frequent

  Q583. What is an exception and exception handling in Java ?Core Java
Ans. An Exception in java is the occurrence during computation that is anomalous and is not expected.

Exception handling is the mechanism which is used to handle such situations.


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

   Like         Discuss         Correct / Improve     exception handling     Asked in 18 Companies      basic        frequent

 Q584. When is the situation when finally section won't execute ?Core Java
Ans. If the process / app is abruptly killed or terminated.

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

   Like         Discuss         Correct / Improve     exception handling  finally     Asked in 2 Companies      intermediate
Try 1 Question(s) Test

  Q585. What is database Normalization ?Database
Ans. https://en.wikipedia.org/wiki/Database_normalization

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

   Like         Discuss         Correct / Improve     normalization  database     Asked in 35 Companies      intermediate        frequent

  Q586. Why java doesn't support multiple Inheritance ?

or

Explain Java Diamond Problem.		Core Java
Ans. class A {
void test() {
System.out.println("test() method");
}
}

class B {
void test() {
System.out.println("test() method");
}
}

Suppose if Java allows multiple inheritance like this,

class C extends A, B {
}

A and B test() methods are inheriting to C class.

So which test() method C class will take? As A & B class test() methods are different , So here we would Facing Ambiguity.

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

   Like         Discuss         Correct / Improve     multiple inheritance  object oriented programming (oops)  oops concepts  diamond problem     Asked in 20 Companies      basic        frequent

 Q587. Does java supports operator overloading ?Core Java
Ans. No

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

   Like         Discuss         Correct / Improve     operator overloading     Asked in 1 Companies      basic

 Q588. Which operators in Java have highest precedence ?Core Java
Ans. Braces, i.e () and [] have the highest precedence

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

   Like         Discuss         Correct / Improve     java operators

 Q589. What is the difference between for and foreach loop in java ? Which one should be used in which cases ?

Core Java
Ans. 1. for loop in java is used with a counter as following

for(int counter=0;counter < 50;counter++){
System.out.println(list.get(counter));
}

for iterating and printing the contents of a collection

whereas foreach loop can be specified directly without the use of counter

for(String str:list){
System.out.println(list.get(counter));
}

2. for Each loop syntax is more clean if we have to iterate over the elements of a collection and we need not keep track of the record count

3. For is preferred when we need loops without the usage of collections or Array of objects and entirely primitives are being used

4. for loop is preferred if we need to keep track of record count and have to perform some action of the basis of that. For example - If we have to print something after every 5 records, With for each loop in such case, we will have to keep a separate counter.

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

   Like         Discuss         Correct / Improve     loop  for loop  control statements  loop statement  foreach loop  for vs foreach loop

 Q590. 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/

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

   Like         Discuss         Correct / Improve     ServletConfig  ServletContext     Asked in 1 Companies

 Q591. What is the difference between following code segments

1.

try {
for(int i=0;i<100;i++){
calculate(i);
}
} catch (Exception ex) {
System.out.println("Error while processing")
}

and

2.

for(int i=0;i<100;i++){
try {
calculate(i);
} catch (Exception ex) {
System.out.println("Error while processing")
}
}
Core Java
Ans. In first case the whole loop will terminate as soon as any exception happens in the method calculate ( assuming calculate method is not handling its exception and those are thrown back at the calling method )

In Second case exception will be caught for individual iteration and hence it wont break the loop and will continue for the next iteration.

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

   Like         Discuss         Correct / Improve     exception handling  try catch     Asked in 1 Companies

 Q592. What do you look for when you do code review ?Core Java
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     Asked in 1 Companies      intermediate        frequent

 Q593. Can we have an entity in hibernate without primary Key ?Hibernate
Ans. No, Every entity in hibernate needs to have a key, either primary or composite.

If we dont have a primary key on table, there are various ways this problem can be countered.

1. By using composite key on entity ( make sure that the appropriate unique constraint in defined on columns in Database )

2. By mapping Id in entity to ROWID of table.

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

   Like         Discuss         Correct / Improve     hibernate entity  hibernate

 Q594. Which type of memory is cleaned / recovered by garbage collection - stack or heap ?Core Java
Ans. Heap memory.

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

   Like         Discuss         Correct / Improve     memory management  stack  heap  garbage collection     Asked in 2 Companies

 Q595. How to make sure that only one instance is created in Singleton Pattern ?Core Java
Ans. public class SingleTon {
private SingleTon() {
if (singleTon != null) {
throw new RuntimeException("cant not create the object");
}
}
public Object clone() throws CloneNotSupportedException {
throw new CloneNotSupportedException("can not be create");
}

static private volatile SingleTon singleTon;
public static SingleTon getInstance() {
SingleTon singleTon = this.sample;
if (singleTon == null) {
synchronized (this) {
singleTon = this.singleTon;
if (singleTon == null) {
singleTon = this.singleton = new SingleTon();
}
}
}
return singleTon;
}
}

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

   Like         Discuss         Correct / Improve     singleton  design pattern     Asked in 2 Companies

 Q596. With a Table employee having columns Id,Name,ManagerEmployeeId, Write a SQL to find the Manager with maximum number of employees ?Database
Ans. Select Name from EMPLOYEE where ID in (Select ManagerEmployeeId from EMPLOYEE
Group By ManagerEmployeeId
order by count(Id)
LIMIT 1)

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

   Like         Discuss         Correct / Improve     database  sql     Asked in 1 Companies

 Q597. What is serialVersionUID ?Core Java
Ans. Everytime an object is serialized the java serialization mechanism automatically computes a hash value by passing the meta information for the class. This id is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization

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

   Like         Discuss         Correct / Improve     serialVersionUID  serialization     Asked in 3 Companies      expert        rare

 Q598. What is the advantage of using static final or constant variables in Java ? Core Java
Ans. Better Control - If the value is being used at multiple locations , that can be controlled better from single place. Any change would only require making single change.

Meaning , Aliasing and Better Readability - Sometimes its easy to read the value by its meaning or alias ( 0 as ZERO or 0 as NEUTRAL_VALUE ).


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

   Like         Discuss         Correct / Improve     static final  final variable  variable constants

 Q599. What could be the problems due to the usage of static methods and elements ? Core Java
Ans. static methods and static elements are shared by all objects of a class and hence could create problem.

Static methods are not synchronized by default and hence could create problem when accessed through multiple threads. Static elements are shareable by class and hence state of one object could be altered by another object.

Some limitations with Unit testing as not all mocking framework facilitate mocking them. Power mock allows but Mockito doesn't

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

   Like         Discuss         Correct / Improve     static  static method  static variables

  Q600. What is Maven ?Maven
Ans. Maven is a build automation tool used primarily for Java projects.

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

   Like         Discuss         Correct / Improve     maven  build     Asked in 6 Companies      basic        frequent

previous 30   next 30

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: