Skip to main content

Java J2EE Interview Questions and Answers - Part 7

  1. What is connection pooling?- With servlets, opening a database connection is a major bottleneck because we are creating and tearing down a new connection for every page request and the time taken to create connection will be more. Creating a connection pool is an ideal approach for a complicated servlet. With a connection pool, we can duplicate only the resources we need to duplicate rather than the entire servlet. A connection pool can also intelligently manage the size of the pool and make sure each connection remains valid. A number of connection pool packages are currently available. Some like DbConnectionBroker are freely available from Java Exchange Works by creating an object that dispenses connections and connection Ids on request. The ConnectionPool class maintains a Hastable, using Connection objects as keys and Boolean values as stored values. The Boolean value indicates whether a connection is in use or not. A program calls getConnection() method of the ConnectionPool for getting Connection object it can use; it calls returnConnection() to give the connection back to the pool.
  2. Why should we go for interservlet communication?- Servlets running together in the same server communicate with each other in several ways. The three major reasons to use interservlet communication are: a) Direct servlet manipulation - allows to gain access to the other currently loaded servlets and perform certain tasks (through the ServletContext object) b) Servlet reuse - allows the servlet to reuse the public methods of another servlet. c) Servlet collaboration - requires to communicate with each other by sharing specific information (through method invocation)
  3. Is it possible to call servlet with parameters in the URL?- Yes. You can call a servlet with parameters in the syntax as (?Param1 = xxx || m2 = yyy).

 

  1. What is Servlet chaining?- Servlet chaining is a technique in which two or more servlets can cooperate in servicing a single request. In servlet chaining, one servlet’s output is piped to the next servlet’s input. This process continues until the last servlet is reached. Its output is then sent back to the client.
  2. How do servlets handle multiple simultaneous requests?- The server has multiple threads that are available to handle requests. When a request comes in, it is assigned to a thread, which calls a service method (for example: doGet(), doPost() and service()) of the servlet. For this reason, a single servlet object can have its service methods called by many threads at once.
  3. What is the difference between TCP/IP and UDP?- TCP/IP is a two-way communication between the client and the server and it is a reliable and there is a confirmation regarding reaching the message to the destination. It is like a phone call. UDP is a one-way communication only between the client and the server and it is not a reliable and there is no confirmation regarding reaching the message to the destination. It is like a postal mail.
  1. What is Inet address?- Every computer connected to a network has an IP address. An IP address is a number that uniquely identifies each computer on the Net. An IP address is a 32-bit number.
  2. What is Domain Naming Service(DNS)?- It is very difficult to remember a set of numbers(IP address) to connect to the Internet. The Domain Naming Service(DNS) is used to overcome this problem. It maps one particular IP address to a string of characters. For example, www. mascom. com implies com is the domain name reserved for US commercial sites, moscom is the name of the company and www is the name of the specific computer, which is mascom’s server.
  3. What is URL?- URL stands for Uniform Resource Locator and it points to resource files on the Internet. URL has four components: http://www. address. com:80/index.html, where http - protocol name, address - IP address or host name, 80 - port number and index.html - file path.
  1. What is RMI and steps involved in developing an RMI object?- Remote Method Invocation (RMI) allows java object that executes on one machine and to invoke the method of a Java object to execute on another machine. The steps involved in developing an RMI object are: a) Define the interfaces b) Implementing these interfaces c) Compile the interfaces and their implementations with the java compiler d) Compile the server implementation with RMI compiler e) Run the RMI registry f) Run the application
  2. What is RMI architecture?- RMI architecture consists of four layers and each layer performs specific functions: a) Application layer - contains the actual object definition. b) Proxy layer - consists of stub and skeleton. c) Remote Reference layer - gets the stream of bytes from the transport layer and sends it to the proxy layer. d) Transportation layer - responsible for handling the actual machine-to-machine communication.
  3. what is UnicastRemoteObject?- All remote objects must extend UnicastRemoteObject, which provides functionality that is needed to make objects available from remote machines.
  1. Explain the methods, rebind() and lookup() in Naming class?- rebind() of the Naming class(found in java. rmi) is used to update the RMI registry on the server machine. Naming. rebind(”AddSever”, AddServerImpl); lookup() of the Naming class accepts one argument, the rmi URL and returns a reference to an object of type AddServerImpl.
  2. What is a Java Bean?- A Java Bean is a software component that has been designed to be reusable in a variety of different environments.
  3. What is a Jar file?- Jar file allows to efficiently deploying a set of classes and their associated resources. The elements in a jar file are compressed, which makes downloading a Jar file much faster than separately downloading several uncompressed files. The package java. util. zip contains classes that read and write jar files.

Comments

Post a Comment

Popular Posts

DOT NET Interview Questions with Answers

When not to use Design Patterns?Do not use design patterns in any of the following situations.• When the software being designed would not change with time.• When the requirements of the source code of the application are unique.If any of the above applies in the current software design, there is no need to apply design patterns in the current design and increase unnecessary complexity in the design.When to use Design Patterns?Design Patterns are particularly useful in one of the following scenarios.• When the software application would change in due course of time.• When the application contains source code that involves object creation and event notification.Benefits of Design Patterns:The following are some of the major advantages of using Design Patterns in software development.• Flexibility• Adaptability to change• ReusabilityWhat are Design Patterns?A Design Pattern essentially consists of a problem in a software design and a solution to the same. In Design Patterns each pattern…

Job Posting - Assistant Managers / Deputy Managers / Managers for Designs.

Dear Colleagues,Our present employees are considered as a very important recruitment base and for some positions they are even the primary source of recruitment.We are looking for Assistant Managers / Deputy Manager / Managers for Designs division, to be based at Chennai / Hyderabad / Mumbai. The incumbent should be a self motivated and self driven team leader who can lead a team of engineers and draughtsmen. The job involves design of Cement Plant and allied structures for Indian and International clients.Interested candidates may apply by e-mail to SRRS-IN@flsmidth.com (for openings in Mumbai and Chennai) and to KKB-IN@flsmidth.com (for openings in Hyderabad) with their detailed CV on or before 10 Feb 2010.The details of the openings are as follows :PositionAssistant Managers / Deputy Managers / ManagersDepartmentDesignsJob ResponsibilityAllocating designs / drafting to juniors / draughtsmenProviding necessary inputs to enable them to do the allocated work.Checking of desi…

Walk-in interview on 27th March'10 in Bangalore @ TCS

Use this link, if unable to view the page Tata Consultancy Services (TCS) has endeavoured to help clients solve business challenges across diverse platforms and practices spread across multiple geographies. We, at TCS, offer you an opportunity to be a part of this dynamic team environment that is fulfilling, both professionally and personally.• "Industry Excellence Award 2008" (Institution of Engineers, India)
• "5-Year Multi-Million Dollar Deal" as ArvinMeritor's Global Engineering Partner
• "Best Use of Technology in Recruitment" (Recruiting and Staffing Best in Class -
     RASBIC Awards : 2009-2010)
Web Technologies

JAVA
– JAVA development experience

Microsoft Technologies (MS)

MOSS

.Net Designers
– Microsoft .Net, Oracle, IBM MQ
– Technical design experience
– Multi-engine/multithreading concepts
– Windows service experience

Business Intelligence / Knowledge Management (BI-KM)

Informatica Designer / Developer
– Informatica design / development experience

F…

.Net Framework Interview questions with answers

What do you know about BCL?The BCL (Base Class Library) is a combination of classes or we can say that it’s a library of functionalities and types available to all languages that used in .NET Framework. To make the programmer job more easier dot net gave a advantage to includes the BCL in order to collect a large number of common functions, just like to read a file and write to file, graphic rendering, database interaction, and XML document manipulation at one place . The scope of this is large and standard libraries for most other languages, including C++, and would be comparable in scope to the standard libraries is just like Java. The BCL is sometimes incorrectly referred to as the Framework Class Library (FCL), which is a superset including the Microsoft namespaces.In Assembly which work as GacBrowser ?The GACPicker class allows the user to select an assembly from the Global Assembly Cache. It does this by looking at the filesystem representation of the GAC, since there appears to…

ASP.NET 3.5 interview questions with answers

The IHttpHandler and IHttpHandlerFactory interfaces ?The IHttpHandler interface is implemented by all the handlers. The interface consists of one property called IsReusable. The IsReusable property gets a value indicating whether another request can use the IHttpHandler instance. The method ProcessRequest() allows you to process the current request. This is the core place where all your code goes. This method receives a parameter of type HttpContext using which you can access the intrinsic objects such as Request and Response. The IHttpHandlerFactory interface consists of two methods - GetHandler and ReleaseHandler. The GetHandler() method instantiates the required HTTP handler based on some condition and returns it back to ASP.NET. The ReleaseHandler() method allows the factory to reuse an existing handler.Does .NET CLR and SQL SERVER run in different process?Dot Net CLR and all .net realtes application and Sql Server run in same process or we can say that that on the same address be…

Wipro Infotech Walk-in for Freshers: Oct 31

Freshers IT Job Opening at Wipro InfotechExperience: 0 - 1 Years

Location: Pune

Education:
UG - Any Graduate - Any Specialization  
PG - Any PG Course - Any Specialization

Industry Type: IT-Hardware & Networking

Functional Area: IT-Support, Telecom, Hardware
Job Description:
Walk-in on 31st October at  Wipro Limited 5th Floor, C-Wing, Godrej Eternia, Old Pune - Mumbai Road, Near Shopper's Stop, Shivajinagar, Pune

Timings- 10:00am - 4:00pm



Contact person - Deepa Raman

Wipro is looking for candidates with 6 months to 1 year experience who can join immediately. The role will be on direct contract with Wipro.



Skills Required -
* Good communication & grammatical skills
* Basic understanding of networking terminologies
* Knowledge of workflow management tools like Clarify and Remedy would be desired
* Candidate should be willing to work in a 24/7 shift


Desired Candidate Profile
Walk-in on 31st October at Wipro Limited 5th Floor, C-Wing, G…

Contact Form

Name

Email *

Message *