Interview Question and Answers | Search Coding Interview Questions

Interview Questions and Answers - Order By Newest

Q511. Is String final in Java ?

Core Java

Ans. Strings are immutable in Java and not final.

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

_{Like Discuss Correct / Improve is string final final string immutable immutability immutability}

Q512. Write a program for LinkedList, with method to append node and traversing the list ?

Algorithm

Ans. public class LinkedList {

   Node start = null;
   Node head = null;

   class Node {
      Integer body;
      Node nextNode;

      Node(Integer value) {
         body = value;
      }
   }

   private void addNodeToEnd(Integer value) {
      if (start == null) {
         start = new Node(value);
         head = start;
         head.nextNode = null;
         return;
      }

      while (head.nextNode != null) {
         head = head.nextNode;
      }

      head.nextNode = new Node(value);
   }

   private void traverse() {
      head = start;
      while (head != null) {
         System.out.println(head.body);
         head = head.nextNode;
      }
   }

   public static void main(String[] args) {
      LinkedList ll = new LinkedList();

      ll.addNodeToEnd(5);
      ll.addNodeToEnd(10);
      ll.addNodeToEnd(15);

      ll.traverse();

   }
}

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

_{Like Discuss Correct / Improve LinkedList Data structures Algorithm}

Q513. Write method to delete Node from a LinkedList.

Data Structure

Ans. public class LinkedList {

   Node start = null;
   Node head = null;

   class Node {
      Integer body;
      Node nextNode;

      Node(Integer value) {
         body = value;
      }
   }

   private void addNodeToEnd(Integer value) {
      if (start == null) {
         start = new Node(value);
         head = start;
         head.nextNode = null;
         return;
      }

      while (head.nextNode != null) {
         head = head.nextNode;
      }

      head.nextNode = new Node(value);
   }

   private void deleteNode(Integer value) {
      head = start;
      while (head.nextNode != null) {
         if(head.nextNode.body == value){
            head.nextNode = head.nextNode.nextNode;
         }

         head = head.nextNode;
      }
   }



   private void traverse() {
      head = start;
      while (head != null) {
         System.out.println(head.body);
         head = head.nextNode;
      }
   }

   public static void main(String[] args) {
      LinkedList ll = new LinkedList();

      ll.addNodeToEnd(5);
      ll.addNodeToEnd(10);
      ll.addNodeToEnd(15);

      ll.traverse();

      ll.deleteNode(10);

      ll.traverse();

   }
}

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

_{Like Discuss Correct / Improve linkedlist delete node from linkedlist}

Q514. What are ascii values for capital and lower case alphabets ?

Core Java

Ans. 65 to 90 for capital case alphabets

97 to 122 for lower case alphabets

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

_{Like Discuss Correct / Improve ascii character char}

Q515. What is the difference between pop and peek function of stack ?

Data Structure

Ans. pop method pulls the top element from the stack and then move the top to the next element whereas peek only get the top element but doesn't move the top.

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

_{Like Discuss Correct / Improve stack}

Q516. How can we ensure thread safety in static method ?

Core Java

Ans. By using synchronized static method or synchronized block

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

_{Like Discuss Correct / Improve threads synchronization static methods Asked in 2 Companies intermediate}

Q517. Is there any schema in mongo DB ?

MongoDB

Ans. There is schema in mongo-db but the schema need not to be defined before creating collection.

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

_{Like Discuss Correct / Improve mongodb nosql bigdata Asked in 1 Companies}

Q518. Write a method it will return reverse of the string(with out using reverse method of String or StringBuffer)

Core Java

Ans. String s1 = "akhilesh";
char[] ch = s1.toCharArray();
for (int i = ch.length-1 ; i >=0 ; i--) {
System.out.print(ch[i]);
}

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

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q519. 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}

Q520. Which collection stores element in insertion order ?

Core Java

Ans. LinkedList maintains the insertion order in collection.

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

_{Like Discuss Correct / Improve collections Asked in 1 Companies}

Q521. What are the reasons to choose between reserved and on demand instances ?

Server

Ans. In terms of compute options and configurations, Reserved Instances and On Demand instances are the same. The only difference between the two is that a Reserved Instance is one you rent (reserved) for a fixed duration, and in return you receive a discount on the base price of an On Demand instance.

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

_{Like Discuss Correct / Improve aws aws ec2 aws computing amazon cloud computing amazon ec2 production support Google Cloud Platform (GCP)}

Q522. Find different combination of given String and trace the output

Core Java

Ans. private void permutation(String prefix, String sufix)
{
int ln = sufix.length();
if(ln == 0) {
System.out.println(prefix);
} else {
IntStream.range(0, ln).forEach(i->permutation(prefix sufix.charAt(i), sufix.substring(0,i) sufix.substring(i 1, ln)));
}
}

call:permutation("", "abcdef");

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

_{Like Discuss Correct / Improve String code coding Asked in 1 Companies}

Q523. Can you explain the integration between API Gateway and Lambda if we wish to develop services using these tools.

Amazon Web Services (AWS)

Ans. We can create API gateway and give the name of lambda function in order to be linked with lambda function, deploy the API and whenever request will be made from API it will directly be linked to lambda function to perform further process.

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

_{Like Discuss Correct / Improve aws api gateway aws lambda aws serverless computing amazon cloud serverless computing amazon lambda}

Q524. Why do we need to specify import statement ? Don't you think Java could have been designed in such a way to automatically import everything that's in the class path ?

Core Java

Ans. Java could design it in such a manner but would result in ambiguity if there are multiple files with the same name. The only way to get over it to show the message when you use any such class to provide explicit import with the package prefix. The other problem could be that Java might have to change the early import to Late import and check what's being used to decide what needs to be imported as otherwise you will see errors regarding the ambiguous imports with duplicate file name.

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

_{Like Discuss Correct / Improve import expert}

Q525. Which of the OOP's feature is most important ?

Core Java

Ans. Encapsulation facilitate hiding and restricted access and hence more of a security feature. Encapsulation is definitely a great feature as when applications expand criss cross communication between objects / modules could lead to blunders.

Inheritance facilitates code reuse.

Polymorphism comprise of method overloaded ( which to me is negligible usage ) and method overriding. Method overriding is of great usage as it facilitates concept of interfaces and plugin development.

So it’s Security / Organization vs

Code Reuse / Support for other features like overriding vs

Contracts / Plugin Development facilitating the creation of frameworks / libraries.

Which is more important may vary from application to application , its scale , its use , its sensitivity etc.

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

_{Like Discuss Correct / Improve oops oops features oops concepts}

Q526. Can we have a private default method ?

Core Java

Ans. No. The whole idea of default method is to provide a default definition in case the implementing class intend to provide definition for only some of the methods. Making any of the interface method private would restrict it from being implemented by the implementing class. So default method is an option to provide implementation and not restricting a new definition.

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

_{Like Discuss Correct / Improve java 9 default methods}

Q527. What is the relation between classes in Java ?

Core Java

Ans. There are different types of relationship between classes

Inheritance - Also called is-a relationship, Child class object carries the body of the Parent class when initiated. Moreover there are certain privileges attach to method overriding to the classes related this way. This relationship exist for code reuse, method overriding and interfacing ( through abstract class ).

Composition - Also called has-a relationship. Class objects carries a reference to other class objects when instantiated. This relationship exist for work flow / work delegation.

Inner / Nested class - It’s a relationship that encapsulates the inner class or it’s object within the outer class. This relationship exist for encapsulation / security.

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

_{Like Discuss Correct / Improve}

Q528. Find Fibonacci first n numbers using recursion ?

Core Java

Ans. public int fibonacci(int n) {
if(n == 0)
return 0;
else
if(n == 1)
return 1;
else
return fibonacci(n - 1) fibonacci(n - 2);
}

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

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q529. Have you ever faced problems with rounding decimal places and what were the reasons ?

Core Java

Ans. 1. The problem with double (x*100)/100 doesn't return exact x but few fractions lesser than x and then if you are using floor rounding , it makes a big difference

2. Rounding only after getting a result vs rounding each outcome of 2 operand make difference

3. Usage of inappropriate Rounding mode and Rounding scale.

4. Results with double and BigDecimal

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

_{Like Discuss Correct / Improve BigDecimal double round decimal}

Q530. What is the difference between Observer and Observable ?

RxJava

Ans. Observable is emiting data and Observer is subscribing to catch the data

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

_{Like Discuss Correct / Improve RxJava Design Deaign Pattern}

Q531. Write code to redo and undo without using system functions ?

Design

^{This question was recently asked at 'Aloha Technologies'.This question is still unanswered. Can you please provide an answer.}

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

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q532. What development process / methodology are you using ? Are you using agile ?

General

^{This question was recently asked at 'Spillman Technologies'.This question is still unanswered. Can you please provide an answer.}

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

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q533. How Bitly shortens the URL ?

Web

^{This question was recently asked at 'Symantec'.This question is still unanswered. Can you please provide an answer.}

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

_{Like Discuss Correct / Improve web application url Asked in 1 Companies rare}

Q534. Write code to sort an array.

Algorithm

Ans. https://www.geeksforgeeks.org/arrays-sort-in-java-with-examples/

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

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

Q535. Difference between == and === ?

JavaScript

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

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

_{Like Discuss Correct / Improve == === == vs === Asked in 13 Companies basic frequent}

Q536. Can we have multiple inheritance in java using abstract class ?

Core Java

Ans. No

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

_{Like Discuss Correct / Improve abstract class multiple inheritance object oriented programming (oops) oops concepts Asked in 2 Companies}

Q537. Describe structure of a Web application.

architecture

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

_{Like Discuss Correct / Improve web application Asked in 3 Companies intermediate frequent}

Q538. What are the types of authentication used in Web services ?

Web Service

Ans. Encrypted User Name / Password
Encrypted Password within Cookie
Encrypted Tokens
IP
Client Certificates
Oauth

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

_{Like Discuss Correct / Improve authentication security web service Asked in 12 Companies basic frequent}

Q539. Does use of Final class enforces composition over Inheritance in Java ?

Core Java

Ans. Yes, to a certain extent. But the objective for Final class could be beyond just enforcing composition as certain classes might have been created without inheritance or composition in mind.

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

_{Like Discuss Correct / Improve final class composition object oriented programming (oops) oops concepts inheritance object oriented programming (oops) oops concepts composition object oriented programming (oops) oops concepts vs inheritance object oriented programming (oops) oops concepts expert}

Q540. What could be the reasons for restricting inheritance using final class ?

Core Java

Ans. 1. Enforcing composition over inheritance
2. Restricting overriding of certain methods
3. Final methods are faster than regular instance methods
4. Enforcing Immutability

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

_{Like Discuss Correct / Improve final class reasons for final class restricting inheritance object oriented programming (oops) oops concepts expert}

Search Interview Questions

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