Interview Questions and Answers for 'Technologie' | Search Interview Question

Interview Questions and Answers - Order By Rating

Q241. What is a stream and what are the types of Streams and classes of the Streams?

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 Asked in 3 Companies}

Q242. Advantage of Collection classes over Arrays ?

Core Java

Ans. Collections are re-sizable in nature. We can increase or decrease the size as per recruitment.
Collections can hold both homogeneous and heterogeneous data's.
Every collection follows some standard data structures.
Collection provides many useful built in methods for traversing,sorting and search.

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

_{Like Discuss Correct / Improve java collections collections classes advantages of collections over arrays collections vs arrays basic interview question Asked in 6 Companies basic frequent}

Frequently asked in Infosys and HCL Technologies ( Based on 2 feedback )

Q243. What are different ways of object creation in Java ?

Core Java

Ans. Using new operator - new xyzClass()

Using factory methods - xyzFactory.getInstance( )

Using newInstance( ) method - (Class.forName(xyzClass))emp.newInstance( )

By cloning an already available object - (xyzClass)obj1.clone( )

Sample Code for object initialization using clone

Sample Code for object initialization using getInstance

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

_{Like Discuss Correct / Improve java oops object creation new operator class.forname cloning ebay Asked in 9 Companies expert}

Q244. What are points to consider in terms of access modifier when we are overriding any method?

Core Java

Ans. 1. Overriding method can not be more restrictive than the overridden method.

reason : in case of polymorphism , at object creation jvm look for actual runtime object. jvm does not look for reference type and while calling methods it look for overridden method.

If by means subclass were allowed to change the access modifier on the overriding method, then suddenly at runtime when the JVM invokes the true objects version of the method rather than the reference types version then it will be problematic

2. In case of subclass and superclass define in different package, we can override only those method which have public or protected access.

3. We can not override any private method because private methods can not be inherited and if method can not be inherited then method can not be overridden.

Sample Code for Overriding

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

_{Like Discuss Correct / Improve java overriding access specifier inheritence oops polymorphism object oriented programming (oops) oops concepts runtime polymorphism object oriented programming (oops) oops concepts Asked in 4 Companies}

Try 2 Question(s) Test

Q245. What is constructor chaining and how is it achieved in Java?

Core Java

Ans. A child object constructor always first needs to construct its parent. In Java it is done via an implicit call to the no-args constructor as the first statement

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

_{Like Discuss Correct / Improve java constructor constructor chaining oops call constructor explicitly Asked in 3 Companies}

Try 2 Question(s) Test

Q246. What is the best practice configuration usage for files - pom.xml or settings.xml ?

Maven

Ans. The best practice guideline between settings.xml and pom.xml is that configurations in settings.xml must be specific to the current user and that pom.xml configurations are specific to the project.

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

_{Like Discuss Correct / Improve maven build technologies pom.xml settings.xml architecture technical architect technical lead build management build and release}

Try 1 Question(s) Test

Q247. How can I change the default location of the generated jar when I command "mvn package"?

Maven

Ans. By default, the location of the generated jar is in ${project.build.directory} or in your target directory. We can change this by configuring the outputDirectory of maven-jar-plugin.

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

_{Like Discuss Correct / Improve maven build technologies build management build and release release management}

Q248. What is Maven's order of inheritance?

Maven

Ans. 1. parent pom
2. project pom
3. settings
4. CLI parameters

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

_{Like Discuss Correct / Improve maven build technologies pom.xml parent pom project pom build management}

Try 1 Question(s) Test

Q249. What is a Mojo?

Maven

Ans. A mojo is a Maven plain Old Java Object. Each mojo is an executable goal in Maven, and a plugin is a distribution of one or more related mojos.

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

_{Like Discuss Correct / Improve maven build technologies mojo}

Q250. How do I determine which POM contains missing transitive dependency?

Maven

Ans. run mvn -X

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

_{Like Discuss Correct / Improve maven build technologies pom build management}

Q251. What are different ways to create String Object? Explain.

Core Java

Ans. There are total six ways

1. literals

When we create a String using double quotes, JVM looks in the String pool to find if any other String is stored with same value. If found, it just returns the reference to that String object else it creates a new String object with given value and stores it in the String pool.

2. new keyword

When we use new operator, JVM creates the String object but dont store it into the String Pool. We can use intern() method to store the String object into String pool or return the reference if there is already a String with equal value present in the pool.

3. string buffer
4. string builder
5. System.out.println
6. char to string

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

_{Like Discuss Correct / Improve java string class string jvm memory management string pool Asked in 5 Companies basic frequent}

Try 3 Question(s) Test

Q252. Write a method to check if input String is Palindrome?

Core Java

Ans. private static boolean isPalindrome(String str) {

if (str == null)
return false;

StringBuilder strBuilder = new StringBuilder(str);

strBuilder.reverse();

return strBuilder.toString().equals(str);

}

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

_{Like Discuss Correct / Improve java string stringbuilder stringbuilder string class code palindrome Asked in 38 Companies Basic frequent}

Asked multiple times in Capgemini.

Q253. Why Char array is preferred over String for storing password?

Core Java

Ans. String is immutable in java and stored in String pool. Once it's created it stays in the pool until unless garbage collected, so even though we are done with password it's available in memory for longer duration and there is no way to avoid it. It's a security risk because anyone having access to memory dump can find the password as clear text.

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

_{Like Discuss Correct / Improve java string class string immutable immutability string pool garbage collection advanced Asked in 6 Companies Expert}

Q254. Why String is popular HashMap key in Java?

Core Java

Ans. Since String is immutable, its hashcode is cached at the time of creation and it doesnt need to be calculated again. This makes it a great candidate for key in a Map and its processing is fast than other HashMap key objects. This is why String is mostly used Object as HashMap keys.

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

_{Like Discuss Correct / Improve java string class string immutable immutability hashmap immutable immutability hashcode hash code advanced Asked in 2 Companies expert frequent}

Q255. What is the use of HashCode in objects ?

Core Java

Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc.

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

_{Like Discuss Correct / Improve java string hashcode hash code string comparison hashtable Asked in 17 Companies basic frequent}

Frequently asked to fresh graduates and less experienced.

Q256. Difference between Composition and Inheritance ?

Core Java

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 Asked in 12 Companies basic frequent}

Try 2 Question(s) Test

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

Q257. Write a program to reverse a string iteratively and recursively ?

Core Java

Ans. Using String method -

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

Iterative -

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 -

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

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

_{Like Discuss Correct / Improve java string reverse stringbuffer string class code Asked in 6 Companies frequent}

Q258. How to find whether a given integer is odd or even without use of modulus operator in java?

Core Java

Ans. public static void main(String ar[])
{
int n=5;
if((n/2)*2==n)
{
System.out.println("Even Number ");
}
else
{
System.out.println("Odd Number ");
}
}

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

_{Like Discuss Correct / Improve java code coding tricky questions interesting questions modulus operator Asked in 4 Companies frequent}

Very frequently asked in companies using SOA.

Q259. What are RESTful Web Services ?

Rest

Ans. REST or Representational State Transfer is a flexible architecture style for creating web services that recommends the following guidelines -

1. http for client server communication,
2. XML / JSON as formatiing language ,
3. Simple URI as address for the services and,
4. stateless communication.

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

_{Like Discuss Correct / Improve java web services rest java j2ee architecture Asked in 14 Companies intermediate frequent}

Very Frequently asked. Favorite question in walkins and telephonic interviews. Usually among first few questions. Asked in different variants. Must know for intermediate and expert professionals.Among Top 10 frequently asked questions.

Q260. What is rule regarding overriding equals and hashCode method ?

Core Java

Ans. A Class must override the hashCode method if its overriding the equals method.

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

_{Like Discuss Correct / Improve java collections hashcode hash code equals collections Asked in 44 Companies intermediate frequent}

Try 1 Question(s) Test

Q261. What do you mean by "Java is a statically typed language" ?

Core Java

Ans. It means that the type of variables are checked at compile time in Java.The main advantage here is that all kinds of checking can be done by the compiler and hence will reduce bugs.

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

_{Like Discuss Correct / Improve java statically typed language variable declaration Asked in 7 Companies basic frequent}

Q262. What is a ConcurrentHashMap ?

Core Java

Ans. ConcurrentHashMap is a hashMap that allows concurrent modifications from multiple threads as there can be multiple locks on the same hashmap.

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

_{Like Discuss Correct / Improve java collections hashmap map concurrenthashmap concurrenthashmap concurrency general electric ge Asked in 32 Companies rare}

Q263. Can we overload main method in Java ?

Core Java

Ans. Yes, but the overloaded main methods without single String[] argument doesn't get any special status by the JVM. They are just another methods that needs to be called explicitly.

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

_{Like Discuss Correct / Improve java main method overloading yes-no Asked in 6 Companies intermediate frequent}

Frequently asked question in companies using hibernate.

Q264. Difference between first level and second level cache in hibernate ?

Hibernate

Ans. 1. First level cache is enabled by default whereas Second level cache needs to be enabled explicitly.

2. First level Cache came with Hibernate 1.0 whereas Second level cache came with Hibernate 3.0.

3. First level Cache is Session specific whereas Second level cache is shared by sessions that is why First level cache is considered local and second level cache is considered global.

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

_{Like Discuss Correct / Improve hibernate orm hibernate cache architecture technical lead first level cache vs second level cache Asked in 18 Companies Intermediate frequent}

Q265. What are different types of second level cache ?

Hibernate

Ans. 1. EHCache ( Easy Hibernate )
2. OSCache ( Open Symphony )
3. Swarm Cache ( JBoss )
4. Tree Cache ( JBoss )

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

_{Like Discuss Correct / Improve hibernate orm hibernate cache technical lead Asked in 7 Companies}

Very frequently asked Hibernate interview question. Frequently asked in TCS ( based on 2 feedback )

Q266. What are different types of associations in Hibernate ?

Hibernate

Ans. There are 4 types of associations in Hibernate

One to One
One to Many
Many to One
Many to Many

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

_{Like Discuss Correct / Improve hibernate associations Asked in 11 Companies frequent}

Q267. What are the contents of Hibernate configuration file ( hibernate.cfg.xml ) ?

Hibernate

Ans. HBM Files ( Mapping )
DB Connection ( DB Connection String , User Name , Password , Pool Size )
SQL Dialect ( SQL variant to be generated )
Show SQL ( Show / No show SQL on Console )
Auto Commit ( True / False )

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

_{Like Discuss Correct / Improve hibernate configuration barclays Asked in 11 Companies}

Very frequently asked if being interviewed for hibernate. Frequently asked in Tata Consultancy (TCS) and Overstock.com

Q268. Difference between load and get ?

Hibernate

Ans. If id doesnt exist in the DB load throws an exception whereas get returns null in that case.get makes the call to DB immediately whereas load makes the call to proxy.

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

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

Q269. What is lazy fetching in Hibernate ?

Hibernate

Ans. Lazy fetching is the technique of not loading the child objects when parent objects are loaded. By default Hibernate does not load child objects. One can specify whether to load them or not while doing the association.

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

_{Like Discuss Correct / Improve hibernate lazy fetching architecture Asked in 11 Companies frequent}

Try 2 Question(s) Test

Very frequently asked. Favorite question in Walk in Drive of many Indian service companies.

Q270. What is the difference between ArrayList and LinkedList ?

Core Java

Ans. Underlying data structure for ArrayList is Array whereas LinkedList is the linked list and hence have following differences -

1. ArrayList needs continuous memory locations and hence need to be moved to a bigger space if new elements are to be added to a filled array which is not required for LinkedList.

2. Removal and Insertion at specific place in ArrayList requires moving all elements and hence leads to O(n) insertions and removal whereas its constant O(1) for LinkedList.

3. Random access using index in ArrayList is faster than LinkedList which requires traversing the complete list through references.

4. Though Linear Search takes Similar Time for both, Binary Search using LinkedList requires creating new Model called Binary Search Tree which is slower but offers constant time insertion and deletion.

5. For a set of integers you want to sort using quicksort, it's probably faster to use an array; for a set of large structures you want to sort using selection sort, a linked list will be faster.

Sample Code for ArrayList

Sample Code for LinkedList

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

_{Like Discuss Correct / Improve collections java data structures arraylist linkedlist arraylist vs linkedlist Asked in 61 Companies Basic frequent}

Try 1 Question(s) Test

Search Interview Questions

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