Sunday, 8 July 2012
doGet():
protected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, java.io.IOException – is a method of Class HttpServlet. It is called by the server (via the service method) to allow a servlet to handle a client's GET request.
In doGet(), the client’s request parameters are appended to the URL...
Sunday, 8 July 2012 14 Read more »
Monday, 5 March 2012
java.lang.Throwable is the superclass of all the errors and exceptions in java.
...
Monday, 5 March 2012 6 Read more »
Normal 0 false false false MicrosoftInternetExplorer4
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Table Normal";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0in 5.4pt 0in 5.4pt;
mso-para-margin:0in;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
...
Thursday, 1 March 2012
Class GenericServlet :
· It is an abstract class which defines a generic and protocol independent servlet. Here, protocol independent means, by default, it doesn’t contain inherent support for any particular type...
Thursday, 1 March 2012 3 Read more »
Wednesday, 29 February 2012
Interface javax.servlet.Servlet is that interface which defines the ServletLife Cycle methods. So, all servlets must implement this interface, either directly or by extending a class which implements this interface. Instead of directly implementing the Servlet Interface, a servlet can also extend Class GenericServlet (which implements...
Wednesday, 29 February 2012 6 Read more »
Monday, 27 February 2012
Servlet:
Servlet is a server-side (runs within a Web server), Java Programming Language Class which interacts with clients via request-response programming model (example, HTTP Request-Response model).
It can respond to any type of request, but, generally, it is used to extend the application hosted by Web Server by providing...
Monday, 27 February 2012 166 Read more »
Friday, 24 February 2012
By default, all enums implicitly extend java.lang.Enum. And as we know, Java doesn't support multiple inheritance, an enum cannot extend any other class...
Friday, 24 February 2012 1 Read more »
Monday, 20 February 2012
Java Servlet API is that Application Program Interface (API), which defines and describes the contracts between servlets and servers. That means, it contains the set of programs and standard instructions to develop a proper access between a servlet and the server. Servlet API is a part of the official J2EE API. This API...
Monday, 20 February 2012 13 Read more »
Friday, 17 February 2012
If client intentionally turns off the cookies, that means, the client chooses not to join the session. In this situation, until the client turns on the cookies, getSession will return a different session on each request, and isNew will always return true.
Anijit Sarkar...
Friday, 17 February 2012 1 Read more »
Session tracking in Servlets is done by using Interface HttpSession. It helps to identify a client throughout many page requests or visiting a website and to store details about that client.
Whenever a request arrives, it checks for the preexisting session object, to fetch details of the client from there,...
Saturday, 11 February 2012
HTTP stands for HyperText Transfer Protocol, whereas, HTTPS is HyperText Transfer Protocol Secure.
HTTP transmits everything as plan text, while HTTPS provides encrypted communication, so that only the recipient can decrypt and read the information. Basically, HTTPS is a combination of HTTP and SSL (Secure Sockets Layer)....
Saturday, 11 February 2012 18 Read more »
Friday, 10 February 2012
HTTP (HyperText Transfer Protocol):
HTTP is a stateless protocol. That means, It doesn’t contain any information regarding the client.
It works as a request-response protocol in the client-side computing model.
As it’s an Application Layer Protocol within the Framework Internet Protocol Suite, needs...
Friday, 10 February 2012 6 Read more »
Thursday, 9 February 2012
HTTP is a stateless protocol. That means it doesn’t contain any information regarding the client, where it’s coming from. So it’s hard for Web Server to know whether it’s a request from a new user or not. This behavior can cause many problems.
For example, suppose a user has logged into a site. Now he wants to go to a particular...
Thursday, 9 February 2012 0 Read more »
Monday, 6 February 2012
Web Container / Servlet Container / Servlet Engine :
In J2EE Architecture, a web container(also known as servlet container or servlet engine), is used to manage the components like servlets, JSP.
It provides a runtime environment to the components of J2EE.
When ever web server receive a request it forward it to web container which deals...
Monday, 6 February 2012 123 Read more »
Saturday, 4 February 2012
Life cycle of a servlet starts when its first load in the memory space in web server and ends when unloaded from the server memory. we can divide this in 3 steps.
STEP 1: INITIALIZATION:
Server loads the servlet class.
Creates an instance for the servlet class.
Server initializes the instance by calling init() method.
...
Saturday, 4 February 2012 69 Read more »
Tuesday, 31 January 2012
Class FileInputStream:
It is use for reading stream of data from a file in the form of raw bytes(8-bit).
Very useful to read image.
It can also read character files.
Hierarchy of Class FileInputStream:
...
Tuesday, 31 January 2012 4 Read more »
Sunday, 29 January 2012
The class which is defined within another class is called nested class.
It can be divided into 2 types. They are - static nested class & non-static nested class
Static Nested Class:
Nested class which is declared static is static nested class.
Its methods & variables are associated...
Sunday, 29 January 2012 21 Read more »
Saturday, 28 January 2012
throw is used to throw an exception in a program, explicitly.
Whereas, throws is included in the method's declaration part, with a list of exceptions that the method can possible throw. It is necessary for all exceptions(except for Error & RuntimeException & their sub-classes).
...
Saturday, 28 January 2012 26 Read more »
Friday, 27 January 2012
String class :Once an object is created and initialized, it can't be changed because it is Immutable.
String object can be created Implicitly and Explicitly.
StringBuffer class :
StringBuffer class is mutable(can be modified), length and content can be changed through certain method calls.
It creates object Explicitly. ...
Friday, 27 January 2012 1 Read more »
Wednesday, 25 January 2012
The class Object(java.lang.Object), is the super class of all classes in Java...
Wednesday, 25 January 2012 54 Read more »
Saturday, 21 January 2012
In Java, under Throwable class, there are 2 sub-classes named Exception and Error.
Exception class:
It is used for exceptional conditions that user programs should catch.
It's also the class that you will sub-class to create your own custom exception types.
For example, NullPointerException will be thrown if you try using a null reference...
Saturday, 21 January 2012 5 Read more »
Thursday, 19 January 2012
Container is a component which can contain other components inside itself. It is also an instance of a subclass of java.awt.Container, which extends java.awt.Component.
An applet is a container.
Containers include windows, frames, dialogs, and panels.
As a Container itself is a component, it can contain...
Thursday, 19 January 2012 6 Read more »
Wednesday, 18 January 2012
In Java, there are lots of sub-classes under java.lang.Exception class. we can divide these sub-classes into 2 types on the basis of compile-time checking.The types are - Checked Exception & Unchecked Exception.
Checked Exception: Except RuntimeException( java.lang.RuntimeException) class, all sub-classes of Exception are checked exception.
These exceptions need to include in a method's throws list, because these...
Wednesday, 18 January 2012 1 Read more »
Wrapper class is a special type of class that's used to make primitive variables into objects, so that the primitives can be included in activities reserved for objects, like as being added to Collections, or returned from a method with an object return value. It simply wraps or encapsulates a single value for the primitive...
Tuesday, 17 January 2012
1. Interface Externalizable Normal 0 false false false MicrosoftInternetExplorer4
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Table Normal";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0in 5.4pt 0in 5.4pt;
mso-para-margin:0in;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
...
Tuesday, 17 January 2012 0 Read more »
1. An object needs to be serialized, when it's need to be sent over the network.
2. If
the state of an object is to be saved, objects need to be serialized....
Interface Serializable has no methods, it's empty...
By implementing
an interface Serializable in the
class whose instances are to be serialized.Then passing the instance to the ObjectOutputStream which is connected to a
fileoutputstream. This will save the object to a file.
Example:
Now, we will see a practical implementation of serialization...
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