Javascript - Interview Questions and Answers for 'At' | Search Java Interview Question

Javascript - Interview Questions and Answers for 'At' - 37 question(s) found - Order By Newest

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

Q1. Write a Program to reverse a string iteratively and recursively

Ans. Using String method -

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

Iterative -

Strategy - Loop through each character of a String from last to first and append the character to StringBuilder / StringBuffer

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 -

Strategy - Call the method with substring starting from 2nd character recursively till we have just 1 character.

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

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Q2. What is a cookie ?

Java EE

^{admin
info@buggybread.com}

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.

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Q3. What is event handling ? What is event propagation ?

JavaScript

^{2017-05-20 15:32:05}

Ans. LinkedIn

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Q4. Difference between == and === ?

JavaScript

^{2018-07-04 16:16:18}

Ans. == compares values === is used in scripting languages for comparing two values as well as there data tpe. like in js,php.

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Asked in General Electric online assignment.

Q5. Write a Program for coin changer application. The program should set the cash box with available currency and then should render the exact change. If enough cash is not available , it should present the appropriate message.

Core Java

Ans. import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;

public class CoinChanger {

enum Currency {
DOLLAR(1),QUARTER(.25),DIME(.10),NICKEL(.05),PENNY(.01);

private double currencyValue;

Currency(double value){
currencyValue = value;
}

double getCurrencyValue(){
return this.currencyValue;
}
}

private static Map<Currency, Integer> cashBox;
private static Map<Currency, Integer> change;

static {
cashBox = new TreeMap<Currency, Integer>();
change = new TreeMap<Currency, Integer>();
initializeCashBox();
}

public static void main(String[] args) {
double amountToReturn = 18.79f; // Set the amount to be changed here

for(Entry<Currency, Integer> entry:cashBox.entrySet()){
Currency currency = (Currency)entry.getKey();
int coinCount = (int)(amountToReturn/(entry.getKey().getCurrencyValue()));
int availableCurrency = (int)(entry.getValue());

if(coinCount > availableCurrency){
coinCount = availableCurrency;
}

change.put(currency, coinCount);
if(coinCount > 0){
amountToReturn = amountToReturn - (coinCount * entry.getKey().getCurrencyValue());
}
}

System.out.println(change);

if(amountToReturn > .1){
System.out.println("Not enough cash");
}
}

private static void initializeCashBox(){
//set the cash box
cashBox.put(Currency.DOLLAR, 50);
cashBox.put(Currency.QUARTER, 0);
cashBox.put(Currency.DIME, 50);
cashBox.put(Currency.NICKEL, 50);
cashBox.put(Currency.PENNY, 50);

}
}

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Q6. Write a Program to right shift single character in a string

^{2017-08-24 20:12:56}

Ans. public class RightShiftCharacter {
   public static void main(String args[]) {
      String str = "Hello";

      char[] charArray = str.toCharArray();

      for(int count=charArray.length-1;count>0;count--){
         charArray[count] = charArray[count-1];
      }

      String newString = new StringBuilder().append(charArray).toString();

      System.out.println(newString);
   }
}

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Q7. How can we create objects if we make the constructor private ?

Core Java

a. We can't create objects if constructor is private

b. We can only create objects if we follow singleton pattern

c. We can only create one object

d. We can create new object through static method or static block

Ans.d. We can create new object through static method or static block

Q8. What will be the output of executing following class ?

public class BuggyBread {

static {
System.out.println("Static Block");
}

{
System.out.println("Initialization Block");
}

BuggyBread(){
System.out.println("Constructor");
}

public static void main(String[] args){
System.out.println("Main Method");
}
}

Core Java

a. Static Block
Main Method

b. Static Block
Instance Initialization Block
Main Method

c. Static Block
Constructor
Main Method

d. Static Block
Instance Initialization Block
Constructor
Main Method

Ans.a. Static Block
Main Method

Q9. What will be the output upon executing following class ?

public class BuggyBread {

static {
System.out.println("Static Block");
}

{
System.out.println("Instance Initialization Block");
}

BuggyBread(){
System.out.println("Constructor");
}

public static void main(String[] args){
System.out.println("Main Method");
new BuggyBread();
}
}

Core Java

a. Instance Initialization Block
Constructor
Static Block
Main Method

b. Static Block
Instance Initialization Block
Constructor
Main Method

c. Main Method
Static Block
Instance Initialization Block
Constructor

d. Static Block
Main Method
Instance Initialization Block
Constructor

Ans.d. Static Block
Main Method
Instance Initialization Block
Constructor

Q10. With the following code, Which is a valid way to initialize ?
public class BuggyBread {

   private String element1;

   private String element2;

   private BuggyBread(String element1, String element2){
      this.element1 = element1;
      this.element2 = element2;
   }

   public static class Builder {

      private String element1;

      private String element2;

      Builder(BuggyBread buggybread){
         element1 = buggybread.element1;
         element2 = buggybread.element2;
      }

      Builder withElement1(String element1){
         this.element1 = element1;
         return this;
      }

      Builder withElement2(String element2){
         this.element2 = element2;
         return this;
      }

      BuggyBread build(){
         BuggyBread buggybread = new BuggyBread(element1,element2);
         return buggybread;
      }
   }
}

Core Java

a. BuggyBread buggybread = new BuggyBread();

b. BuggyBread buggybread = new BuggyBread("element1","element2");

c. BuggyBread.Builder builder = new BuggyBread.Builder();

d. BuggyBread.Builder builder = new BuggyBread.Builder("element1","element2");

Ans.d. BuggyBread.Builder builder = new BuggyBread.Builder("element1","element2");

Q11. What will be the output of following ?

public class BuggyBread {

   private int x;
   private Integer y;

   BuggyBread(int x,int y){};

   public static void main(String[] args){
      BuggyBread buggybread = new BuggyBread(1,2);
      System.out.println(buggybread.x);
      System.out.println(buggybread.y);
   }
}    Reference

Core Java

a. 0 0

b. 0 null

c. null 0

d. null null

Ans.b. 0 null

Q12. Which of the following is true for == operator ?

Core Java

a. For primitives, == checks if the variables on left and right have same data type

b. For primitives, == checks if the variables on left and right have same value

c. For Objects, == checks if the references on left and right have same data type

d. For Objects, == checks if the references on left and right have same value

Ans.b. For primitives, == checks if the variables on left and right have same value

Q13. Which of the following is equivalent to following logic ?

Not X && Not Y

Core Java

a. x || Y

b. Not(X || Y)

c. Not(X && Y)

d. Not X && Y

Ans.b. Not(X || Y)

Q14. Which of the following http response means the resource is not found ?

Java EE

a. 500

b. 200

c. 404

d. 400

Ans.c. 404

Q15. What is Dirty Read in Database Transactions ?

Database

a. Data Read by Transaction 2 which hasn't yet updated by Transaction 1

b. Data Read by Transaction 2 which has been updated and commited by Transaction 1

c. Data Read by Transaction 2 which has been updated but not commited by Transaction 1

d. Inability of Transaction 2 to read Data when Transaction 1 is updating.

Ans.c. Data Read by Transaction 2 which has been updated but not commited by Transaction 1

Q16. Which of following annotation is used to initialize objects before executing set of tests ? Reference

Junit

a. @Test

b. @Ignore

c. @After

d. @Before

Ans.d. @Before

Q17. Which of the following is not true for static keyword ? Reference

Core Java

a. Static members are shared by all objects of the class.

b. We can override static methods.

c. Static methods operate on static variables only.

d. Static Elements are accessed using class name.

Ans.b. We can override static methods.

Q18. What is Lazy Initialization in Hibernate ? Reference

Hibernate

a. Feature to load the dependencies from Cache

b. Feature to load all objects and relationships in advance before they can be used

c. Feature to not load dependencies and relationship in advance and load when required

d. Feature to not load the dependencies and relationships at all

Ans.c. Feature to not load dependencies and relationship in advance and load when required

Q19. Which of the following is not the benefit of Lazy Initialization in Hibernate ?

Hibernate

a. Laod When required provides better performance

b. Object stays lighter

c. Less number of Database calls

d. Less load on Database

Ans.c. Less number of Database calls

Q20. The use of volatile keyword facilitates ..

Core Java

a. Making Use of Cache for better Performance

b. Avoiding use of Cache

c. Making use of Backward as well as Forward Cache

d. Keeping only one copy of variable in Cache

Ans.b. Avoiding use of Cache

Q21. Static Polymorphic in Java is achieved through ..

Core Java

a. Method Overloading

b. Method Overriding

c. Variable Overloading

d. Variable Overriding

Ans.a. Method Overloading

Q22. Which of following are serialized ?

Core Java

a. static variables

b. transient variables

c. instance variables

d. method local variables

Ans.c. instance variables

Q23. Which of the following is not true for Hibernate Cache ?

Hibernate

a. First level cache is enabled by default

b. First level Cache is Session specific

c. First level cache is considered global

d. First level Cache came with Hibernate 1.0

Ans.c. First level cache is considered global

Q24. Which of the following is not an Hibernate Annotation

Hibernate

a. @Id

b. @JoinTable

c. @ManyToMany

d. @Autowired

Ans.d. @Autowired

Q25. Which of following is not Spring MVC annotation ?

Spring

a. @Autowired

b. @Controller

c. @JoinColumn

d. @Transactional

Ans.c. @JoinColumn

Q26. In majority of the cases, the following join will give maximum number of results ? Reference

Database

a. Inner Join

b. Outer Join

c. Left Join

d. Right Join

Ans.b. Outer Join

Q27. Which if the following is true for SQL Joins ? Reference

Database

a. Left Join and Right Join gives equal number of Results

b. Outer Join and Inner Join gives equal number of Results

c. Inner Join gives maximum number of results records

d. Inner Join gives minimum number of result records

Ans.d. Inner Join gives minimum number of result records

Q28. Listeners are example of ..

Design

a. Factory design Pattern

b. Abstract Factory Design Pattern

c. Singleton Design Pattern

d. Observer Design Pattern

Ans.d. Observer Design Pattern

Q29. Which of the following is a configuration management tool ?

Tool

a. Github

b. Jira

c. Tomcat

d. Eclipse

Ans.a. Github

Q30. Which of following is not a configuration management tool ?

Tool

a. SVN

b. Jira

c. GitHub

d. Clearcase

Ans.b. Jira

Q31. Which of the following Design pattern has been used with Hibernate Criteria ?

Hibernate

a. Filter

b. Prototype

c. Builder

d. Observer

Ans.a. Filter

Q32. Which of following is not core interface of Hibernate ?

Hibernate

a. Session

b. Transaction

c. SessionFactory

d. TransactionFactory

Ans.d. TransactionFactory

Q33. Which of the following is not true for Prepared Statements ?

Database

a. Prepared Statements provides better performance

b. Prepared Statements prevent SQL Injection attacks

c. Prepared Statements provide ORM capabilities

d. Prepared Statement provides DB side caching

Ans.c. Prepared Statements provide ORM capabilities

Q34. Which of the following session method is used to disassociate / disconnect all objects from the session Reference

Hibernate

a. Clear

b. Evict

c. Close

d. Merge

Ans.a. Clear

Q35. Which of the following session method is used to disassociate / disconnect a particular object / entity from the session

Hibernate

a. Clear

b. Evict

c. Close

d. Merge

Ans.b. Evict

Q36. Which of following is not the resolution for preventing LazyInitializationException?

Hibernate

a. Set fetch=FetchType.EAGER for Dependent entity mapping

b. Make sure that we are accessing the dependent objects before closing the session

c. Make sure that we are accessing the dependent objects after closing the session

d. Wrap the complete access within Transaction

Ans.c. Make sure that we are accessing the dependent objects after closing the session

Q37. Semaphores are used to solve problem of ...

Operating system

a. Race Condition

b. Process Synchronization

c. Mutual Exclusion

d. All of above

Ans.d. All of above

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