Interview Questions and Answers - Order By Newest Q1101. What is a Java Bean ? How is it different from other Java classes ?
Ans. A Java bean is a class which abides by following conventions:
Core of the object is member elements and not operations ( methods )
Member Elements can be accessed by getters (and setters if those properties are not read-only).
serializable. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java bean   javabean   pojo   classes basic   frequent Q1102. What is ADT or Abtstract Data Type ? Core Java
Ans. ADT is a container which holds different types of objects with specifications.
For example - Stack, Array, Liked list, Tree Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  data types  abstract data types Q1103. Find the repeating number using O(n) time and constant space. Algorithm
Ans. http://www.geeksforgeeks.org/find-duplicates-in-on-time-and-constant-extra-space/ Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  algorithm   program   code   coding  makemytrip.com Q1104. Write a method to convert all elements of a set to lower case. Core Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=Method+to+convert+all+elements+of+a+collection&category=code Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  code  coding  string  String.toLowerCase  set  collections Q1105. Write java code to Get all words from a String and display them Core Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=+Get+all+words+from+a+String&category=code Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  string   get all words from strings   string.splitRecently asked in Sophos Q1106. Write a Method to get a map of words and their count by passing in the string Core Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=Method+to+get+a+map+of+words&category=code Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  map  collections Asked in 2 Companies intermediate Q1107. Write code for singleton class Design
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=singleton+class&category=code Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  singleton  code  coding  design pattern Asked in 1 Companies Intermediate   frequent Q1108. Have you ever looked into internal implementation of Java Collections ?
Ans. Yeah, I once looked into implementation of TreeSet and TreeMap just for learning. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections Q1109. How is static and dynamic polymorphism achieved in Java ? Core Java
Ans. Static polymorphism is the polymorphic resolution identified at compile time and is achieved through function overloading whereas dynamic polymorphism is the polymorphic resolution identified at runtime and is achieved through method overriding. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  static polymorphism  object oriented programming (oops)  oops concepts   dynamic polymorphism  object oriented programming (oops)  oops concepts   polymorphism  object oriented programming (oops)  oops concepts   overloading   overriding   broadridg Asked in 1 Companies basic   frequent Q1110. Why can't we declare a class abstract as well as final ? Core Java
Ans. Abstract means that the class is only meant to be subclassed whereas final means that it cannot be subclassed so both concepts - abstract and final are actually mutually exclusive and hence not permitted together. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  abstract   final   java keywords Asked in 1 Companies Q1111. Write a program / method to input few numbers and then print the sum.
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=946 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  code  coding  scanner basic Very frequently asked to fresh graduates. Frequently asked in NSEiT and Accenture India Q1112. Write a program to Generate prime numbers till a given number Core Java
Ans. public class Main {
public static void main(String args[]) {
int number = 2;
int count = 0;
long sum = 0;
int givenNumber = 1000;
while (count < givenNumber) {
if (isPrimeNumber(number)) {
sum = number;
count;
}
number;
}
System.out.println(sum);
}
private static boolean isPrimeNumber(int number) {
for (int i = 2; i <= number / 2; i) {
if (number % i == 0) {
return false;
}
}
return true;
}
} Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  generate prime numbers  code  coding Asked in 5 Companies basic   frequent Q1113. Write a program to calculate factorial of a number using recursion Core Java
Ans.
public class Factorial {
public static void main(String[] args){
int x = 5;
System.out.println(calculateFactorial(x));
}
private static int calculateFactorial(int x){
if(x==1){
return 1;
}
return x * calculateFactorial(x-1);
}
} Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  factorial  calculate factorial  code  coding  recursion Asked in 1 Companies basic Q1114. Write code for the usage of Builder Design Pattern
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=964 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  builder design pattern  builder pattern  code  coding intermediate Q1115. Write code for constructor overloading Core Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=965 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  constructor overloading  code  coding Asked in 2 Companies basic Q1116. Write code to check if an integer is odd or even using ternary operator
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=963 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  ternary operator  code  coding Q1117. Write code to sort elements of a set
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=952 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  set  collections  sorting  treeset  code  coding Q1118. In the following code , how many methods needs to be implemented in Class B ?
public interface A{
public void method1();
public void method2();
public void method3();
}
abstract class B implements A{
} Core Java
Ans. As Class B has been declared abstract , we can either implement any of these methods and just declare rest of them abstract. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  interfaces  abstract classes  code  coding Try 2 Question(s) Test Q1119. What will the following code print ?
Integer a = 100, b =100;
Integer c = 1000, d = 1000;
System.out.println(a == b);
System.out.println(c ==d); Core Java
Ans. false
false Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  object equality  code  coding   frequent Q1120. How is multiple inheritance implemented in Java ? Core Java
Ans. There was no multiple inheritance in java before version 8 as implementing multiple interfaces cannot be termed as inheritance.
With Java 8 , came the concept of default methods wherein the class implementing the interface carries the default implementation from the interface and hence facilitating multiple inheritance. 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   inheritance  object oriented programming (oops)  oops concepts   oops concept Asked in 10 Companies   frequent Q1121. Write a program for Coin Changer application ?
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=979 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  coin changer application  coin changing  general electic (ge) Q1122. What are the new classes in JDK 1.9 ( Java 9 ) ?
Ans. http://www.buggybread.com/2015/05/java-9-new-classes-and-interfaces-in.html Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java9  java 9  jdk1.9  jdk 1.9 Q1123. What is unmodifiable set / unmodifiable map ? How can we create one ?
Ans. It is an unmodifiable / read only view of the underlying collection. We can use
Collections.unmodifiableSet(Set set)
Collections.unmodifiableMap(Map map)
Collections.unmodifiableCollection(Collection collection) Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections  set  unmodifiable set  map  unmodifiable map  unmodifiablemap  unmodifiableset  Collections.unmodifiableCollection  Collections.unmodifiableMap  Collections.unmodifiableSet Q1124. What is the use of MethodHandle ?
Ans. MethodHandle is a modern, more flexible, more typesafe way of doing reflection. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  MethodHandle  Reflection Q1125. What is a Destructor ? Do we have Destructors in Java ? Core Java
Ans. Destructor is used to de-allocate memory allocated by objects.
There are no destructors in Java. Alternatively, Java provides Automatic garbage collection i.e automatically releasing the un-referenced memory. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  destructor  garbage collection Asked in 11 Companies Basic   frequent Try 1 Question(s) Test Q1126. What are JSP Scriptlets?
Ans. Scriptlet allow to write Java code inside JSP like following
<% Java Code %> Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  jsp  jsp scriptlet  scriptlet Q1127. What is struts.devMode?
Ans. The struts.devMode is used to make sure that framework is running in development mode or production mode by setting true or false. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  struts  struts.devMode Q1128. What is use of Revert in SVN? Tools
Ans. Revert your local changes.
There are 2 types of reverts -
1) Local Revert: It will delete all changes from files which you made after updates and before commit.
2) Repo Revert: Upload the changes to previous Repo. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  svn  subversion  version control system  configuration management Asked in 2 Companies Q1129. Can we have multiple threads consuming message stream from a single partition ?
Ans. Yes, by having multiple Consumer Groups. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  apache kafka  kafka  kafka consumer  kafka topic partitions  bigdata  consumer group Q1130. Can we have multiple threads consuming messages from a single partition if we have single Consumer Group ?
Ans. No, we can only have max 1 thread per partition in a single Consumer Group. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  apache kafka  kafka  kafka consumer  kafka topic partitions  bigdata  consumer group