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Servlet Database Access

Servlet Database Access : Data that is shared between Web components and is persistent between invocations of a J2EE application is usually maintained by a database. Web components use the JDBC 2.0 API to access relational databases. The data for the bookstore application is maintained in a database and accessed through the helper class database.BookDB.

For example, ReceiptServletinvokes the…

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Servlet Filter and Servlet Chain

Servlet Filter and Servlet Chain

Servlet Filter and Servelt Chain -We have looked at servlets that take requests directly from the server and return their results directly to the client. Servlets were designed as a generic server extension technology, however, rather than one devoted solely to performing CGIlike functions.

Most web servers that implement servlets have also implemented a feature called servlet chaining, where the…

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ServletRequest Interface

ServletRequest: The common scenario when servlet is asked to handle request (ServletRequest), it typically needs specific information about the request so that it can process the request appropriately. Most frequently, the servlet will retrieve the value of a form variable and use that value in its output.

The servletmay also need access to information about the environment in which it is…

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Servlet Life Cycle

Servlet Life Cycle, The client makes request involving servlet, the server loads and executes the appropriate Java classes. and those classes to generate content, and the server sends the content back to the client. In most cases, the client is a web browser, the server is a web server, and the servlet returns standard HTML. From the web browser’s perspective, this isn’t any different from…

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HttpServlet Class in Servlet

HttpServlet Class in Servlet

HttpServlet Class is an extension of GenericServlet that includes methods for handling HTTP-specific data. HttpServlet provides a number of methods, such as doGet(), doPost(), and doPut(), to handle particular types of HTTP requests (GET, POST, and so on). These methods are usually called by default implementation of the service() method, which figures out what kind of request is being made and…

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JavaScript Event

JavaScript Event : Imagine an interface where the only way to find out whether a key on the keyboard is being pressed is to read the current state of that key. To be able to react to keypresses, you would have to constantly read the key’s state so that you’d catch it before it’s released again. It would be dangerous to perform other time-intensive computations since you might miss a keypress.

A…

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JavaScript Node.js

JavaScript Node.js, a program that allows you to apply your JavaScript skills outside of the browser. With it, you can build anything from small command line tools to HTTP servers that power dynamic websites.

the main concepts that JavaScript Node.jsuses and to give you enough information to write useful programs for it. They do not try to be a complete, or even a thorough, treatment of the…

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JavaScript Scope

JavaScript Scoperefers to the variables that are available to a piece of code at a given time. A lack of understanding of scope can lead to frustrating debugging experiences. When a variable is declared inside of a function using the var keyword, it is only available to code inside of that function — code outside of that function cannot access the variable. On the other hand, functions defined…

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JavaScript "this" Keyword

JavaScript “this” Keyword

In JavaScript “this” Keyword, as in most object-oriented programming languages, this is a special keyword that is used within methods to refer to the object on which a method is being invoked. The value of this is determined using a simple series of steps:

If the function is invoked using Function.call or Function.apply, this will be set to the first argument passed to call/apply. If the first…

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JavaScript Function

The definition expression defines a JavaScript function, and the value of such an expression is the newly defined function. In a sense, a function definition expression is a “function literal” in the same way that an object initializer is an “object literal.”A function definition expression typically consists of the keyword function followed by a comma-separated list of zero or more identifiers…

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JavaScript User Input

JavaScript User Input : Clicks are powerful and easy and you can add an on Click event to pretty much any HTML element, but sometimes you need to be able to ask for input from the user and process it. For that you’ll need a basic form element and a button.

input id='userInput' size=60> <button onClick='userSubmit()'>Submit</button><BR> <P>

Here we create an input field and give it a name of user…

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JavaScript Boolean

JavaScript Boolean, It is often useful to have a value that distinguishes between only two possibilities, like “yes” and “no” or “on” and “off”. For this purpose, JavaScript has Boolean type, which has just two values, true and false, which are written as those words.

JavaScript Boolean valuesare commonly used in JavaScript control structures. For example, the if/else statement in JavaScript…

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OOP Interview Questions and Answers

OOP Interview Questions and Answers

There are still people, for instance, that call Artificial Intelligence to any program that is written in Prolog or Lisp. In the same way, there are those who maintain that any program written in Smalltalk, C++ or Objective C is OOP.  A given application is a hierarchical set of programs (modules) each of which is capable of invoking other programs in the hierarchy. We can herewith list of latest…

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OOAD Interview Questions and Answers

OOAD Interview Questions and Answers

OOAD -Object-Oriented Design: The emphasis in programming methods is primarily on the proper and effective use of particular language mechanisms. By contrast, design methods emphasize the proper and effective structuring of a complex system. We can herewith list of latest and updated OOAD Interview Questions and their answers for fresher’s as well as experienced users.  These JavaScript interview…

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MySQL Interview Questions and Answers

MySQL Interview Questions and Answers

MySQL is a relatively recent entrant into the well-established area of relational database management systems (RDBMs), a concept invented by IBM researcher Edgar Frank Codd in 1970. Despite the arrival of newer types of data repositories over the past 35 years, relational databases remain the workhorses of the information world. We can herewith list of latest and updated MySQL Interview Questions

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JavaScript Interview Questions and Answers

JavaScript Interview Questions and Answers

Javascript is an interpreted language with a C like syntax. While many people brush the language off as nothing more than a browser scripting language, it actually supports many advanced concepts such as object-oriented-programing, recursion, lambda, and closures. We can herewith list of latest and updated JavaScript Interview Questions and their answers for fresher’s as well as experienced…

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MATLAB Interview Questions and Answers

MATLAB Interview Questions and Answers

MATLAB, which is short for Matrix Laboratory, incorporates numerical computation, symbolic computation, graphics, and programming. We can herewith list of latest and updated MATLAB Interview Questionsand their answers for fresher’s as well as experienced users.  These MATLAB interview question covers latest version of MATLAB.  MATLAB is a high-performance language for technical computing. It…