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

Interview Questions and Answers - Order By Rating

Q1561. Tell something about BufferedWriter ? What are flush() and close() used for ?

Ans. BufferedWriter is temporary source for data storage.BufferedWriter is used to write character data to the file.Flush() is method available in B.W which ensures that all data items are written to file including last character.Close() is used to closes the character output stream.

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

_{Like Discuss Correct / Improve java java io input output file handling file io output stream bufferedwriter flush close}

Q1562. What is Scanner class used for ? when was it introduced in Java ?

Core Java

Ans. Scanner class introduced in Java 1.5 for reading Data Stream from the imput device. Previously we used to write code to read a input using DataInputStream. After reading the stream , we can convert into respective data type using in.next() as String ,in.nextInt() as integer, in.nextDouble() as Double etc

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

_{Like Discuss Correct / Improve java java5 scanner file io file input data input stream file handling basic}

Q1563. Whats the purpose of marker interfaces ?

Ans. They just tell the compiler that the objects of the classes implementing the interfaces with no defined methods need to be treated differently.

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

_{Like Discuss Correct / Improve java interfaces marker interfaces clonable serializable basic frequent}

Very frequently asked. Favorite question in Walk in Drive of many Indian service companies. Frequently asked in HCL Technologies, TCS and Accenture.

Q1564. What is the difference between final, finally and finalize() ?

Core Java

Ans. final - constant variable, objects cannot be de-referenced, restricting method overriding, restricting class sub classing.

finally - handles exception. The finally block is optional and provides a mechanism to clean up regardless of what happens within the try block. Use the finally block to close files or to release other system resources like database connections, statements etc.

finalize() - method helps in garbage collection. A method that is invoked before an object is discarded by the garbage collector, allowing it to clean up its state.

Sample Code for final

Sample Code for finally

Sample Code for finalize

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

_{Like Discuss Correct / Improve java oops final finally finalize final vs finally vs finalize Asked in 61 Companies basic frequent}

Try 4 Question(s) Test

Q1565. When do you get ClassCastException?

or

What is ClassCastException ?

Ans. As we only downcast class in the hierarchy, The ClassCastException is thrown to indicate that code has attempted to cast an object to a subclass of which it is not an instance.

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

_{Like Discuss Correct / Improve java oops class casting classcastexception exception error Asked in 4 Companies intermediate frequent}

Try 2 Question(s) Test

Frequently asked to fresh graduates.

Q1566. Explain Thread States ?

Operating System

Ans. Runnable - waiting for its turn to be picked for execution by the thread schedular based on thread priorities.

Running - The processor is actively executing the thread code. It runs until it becomes blocked, or voluntarily gives up its turn.

Waiting: A thread is in a blocked state while it waits for some external processing such as file I/O to finish.

Sleeping - Java threads are forcibly put to sleep (suspended) with Thread.sleep. they can resume using Thread.resume method.

Blocked on I/O - Will move to runnable after I/O condition like reading bytes of data etc changes.

Blocked on synchronization - Will move to Runnable when a lock is acquired.

Dead - The thread is finished working.

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

_{Like Discuss Correct / Improve java threads multi threading scheduling thread states basic interview question Asked in 1 Companies basic frequent}

Try 2 Question(s) Test

Q1567. What are strong, soft, weak and phantom references in Java ?

Core Java

Ans. Garbage Collector wont remove a strong reference.

A soft reference will only get removed if memory is low.

A weak reference will get removed on the next garbage collection cycle.

A phantom reference will be finalized but the memory will not be reclaimed. Can be useful when you want to be notified that an object is about to be collected.

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

_{Like Discuss Correct / Improve java memory management jvm garbage collections references strong reference soft reference weak reference phantom reference architecture Asked in 2 Companies}

Q1568. Difference between yield() and sleeping()?

Ans. When a task invokes yield(), it changes from running state to runnable state. When a task invokes sleep(), it changes from running state to waiting/sleeping state.

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

_{Like Discuss Correct / Improve java threads multi threading scheduling thread states yield sleeping}

Usually asked only to fresh graduates and less experienced developers.

Q1569. What is a daemon thread? Give an Example ?

Ans. These are threads that normally run at a low priority and provide a basic service to a program or programs when activity on a machine is reduced. garbage collector thread is daemon thread.

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

_{Like Discuss Correct / Improve java threads multi threading operating system daemon thread garbage collection Asked in 10 Companies intermediate frequent}

Try 2 Question(s) Test

Q1570. What is the order of method invocation in an applet?

Ans. public void init()
public void start()
public void stop()
public void destroy()

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

_{Like Discuss Correct / Improve java java ui applet swing awt}

Q1571. Name few tools for probing Java Memory Leaks ?

Ans. JProbe, OptimizeIt

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

_{Like Discuss Correct / Improve java tools jvm memory management memory leaks jprobe optimeit architecture technical lead}

Q1572. What is XML ?

Xml

Ans. XML or eXtensible Markup Language is a markup languages for describing data and its metadata.

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

_{Like Discuss Correct / Improve xml markup language basic frequent}

Q1573. Difference between SAX and DOM Parser ?

Xml

Ans. A DOM (Document Object Model) parser creates a tree structure in memory from an input document whereas A SAX (Simple API for XML) parser does not create any internal structure.

A SAX parser serves the client application always only with pieces of the document at any given time whereas A DOM parser always serves the client application with the entire document no matter how much is actually needed by the client.

A SAX parser, however, is much more space efficient in case of a big input document whereas DOM parser is rich in functionality.

Use a DOM Parser if you need to refer to different document areas before giving back the information. Use SAX is you just need unrelated nuclear information from different areas.

Xerces, Crimson are SAX Parsers whereas XercesDOM, SunDOM, OracleDOM are DOM parsers.

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

_{Like Discuss Correct / Improve java xml parsers sax dom parser difference architecture technical lead technical architect markup language sax vs dom Asked in 14 Companies frequent}

Try 1 Question(s) Test

Q1574. What is DTD ?

Xml

Ans. DTD or Document Type Definition is a standard agreed upon way of communication between two parties. Your application can use a standard DTD to verify that data that you receive
from the outside world is valid and can be parsed by your parser.

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

_{Like Discuss Correct / Improve xml markup language dtd document type definition architecture}

Q1575. What is XSD ?

Xml

Ans. XSD or Xml Schema Definition is an extension of DTD. XSD is more powerful and extensible than DTD

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

_{Like Discuss Correct / Improve java xml markup language xsd dtd architecture}

Q1576. What is JAXP ?

Xml

Ans. Stands for Java API for XML Processing. This provides a common interface for creating and using SAX, DOM, and XSLT APIs in Java regardless of which vendorâ€™s implementation is actually being used.

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

_{Like Discuss Correct / Improve java java api xml xml processing jaxp abbreviation technologies}

Q1577. What is JAXB ?

Xml

Ans. Stands for Java API for XML Binding. This standard defines a mechanism for writing out Java objects as XML and for creating Java objects from XML structures.

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

_{Like Discuss Correct / Improve java xml markup language java api for xml binding jaxb abbreviation technologies Asked in 2 Companies}

Q1578. What is marshalling ?

Xml

Ans. Its the process of creating XML structures out of Java Objects which is used to traverse information across the network.

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

_{Like Discuss Correct / Improve xml java api for xml marshalling parser sax dom technologies Asked in 1 Companies}

Q1579. What is unmarshalling ?

Ans. Its the process of creating Java Objects out of XML structures.

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

_{Like Discuss Correct / Improve xml java api for xml unmarshalling parser sax dom architecture Asked in 1 Companies}

Q1580. Which load testing tools have you used ?

Ans. Rational Robot, JMeter, LoadRunner

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

_{Like Discuss Correct / Improve testing load testing rational robot jmeter loadrunner software tester basic rare}

Q1581. What are LDAP servers used for ?

Java EE

Ans. LDAP servers are typically used in J2EE applications to authenticate and authorise users. LDAP servers are hierarchical and are optimized for read access, so likely to be faster than database in providing read access.

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

_{Like Discuss Correct / Improve java j2ee ldap servers authentication authorization architecture technical lead technical architect production support Asked in 1 Companies}

Frequently asked in CTS ( Based on 2 feedback )

Q1582. What is the difference between comparable and comparator in java.util pkg?

Core Java

Ans. Comparable interface is used for single sequence sorting i.e.sorting the objects based on single data member where as comparator interface is used to sort the object based on multiple data members.

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

_{Like Discuss Correct / Improve java java.util comparable comparator collections Asked in 23 Companies basic frequent}

Q1583. What are different modules of spring ?

Spring

Ans. There are seven core modules in spring

Spring MVC
The Core container
O/R mapping
DAO
Application context
Aspect Oriented Programming or AOP
Web module

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications}

Recently asked in TCS , Tech Mahindra, HCL , Accenture and Fidelity.

Q1584. Explain Flow of Spring MVC ?

Spring

Ans. The DispatcherServlet configured in web.xml file receives the request.

The DispatcherServlet finds the appropriate Controller with the help of HandlerMapping and then invokes associated Controller.

Then the Controller executes the logic business logic and then returns ModeAndView object to the DispatcherServlet.

The DispatcherServlet determines the view from the ModelAndView object.

Then the DispatcherServlet passes the model object to the View.

The View is rendered and the Dispatcher Servlet sends the output to the Servlet container.

Finally Servlet Container sends the result back to the user.

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications architecture Asked in 11 Companies Basic frequent}

Q1585. What is Spring configuration file?

Spring

Ans. Spring configuration file is an XML file. This file contains the classes information and describes how these classes are configured and introduced to each other.

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications spring configuration file Asked in 1 Companies}

Q1586. Q: What is default scope of bean in Spring framework?

Spring

Ans. The default scope of bean is Singleton.

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications bean}

Q1587. What bean scopes does Spring support? Explain them.

Spring

Ans. The Spring Framework supports following five scopes -

Singleton
prototype
request
session
global-session

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications beans beans scope at&t fidelity}

Very Frequently asked Spring question.

Q1588. What is bean auto wiring?

Spring

Ans. The Spring container is able to autowire relationships between collaborating beans. This means that it is possible to automatically let Spring resolve collaborators (other beans) for your bean by inspecting the contents of the BeanFactory without using and elements.

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

_{Like Discuss Correct / Improve j2ee spring mvc frameworks web applications autowiring beans at&t ge Asked in 9 Companies frequent}

Q1589. Difference between socket and servlet ?

Java EE

Ans. servlet is a small, server-resident program that typically runs automatically in response to user input.
A network socket is an endpoint of an inter-process communication flow across a computer network.

We can think of it as a difference between door and gate. They are similar as they both are entry points but they are different as they are put up at different areas.

Sockets are for low-level network communication whereas Servlets are for implementing websites and web services

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

_{Like Discuss Correct / Improve java j2ee networking servlet socket difference between.java.net technologies architecture}

Q1590. Difference Between this() and super() ?

Core Java

Ans. 1.this is a reference to the current object in which this keyword is used whereas super is a reference used to access members specific to the parent Class.

2.this is primarily used for accessing member variables if local variables have same name, for constructor chaining and for passing itself to some method whereas super is primarily used to initialize base class members within derived class constructor.

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

_{Like Discuss Correct / Improve java oops class objects inheritence constructor this super this vs super Asked in 1 Companies}

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.