Crack SCWCD

SCWCD books

2008-12-29T23:41:00.000-08:00

Books for SCWCD Exam1)Head First Servlets and JSP: Passing the Sun Certified Web Component Developer Exam (SCWCD)2) SCWCD Exam study kit by Deshmukh (Manning Publications)3)Sun Certified Web Component Developer Study Guide 4)Professional SCWCD Certification 1 and 2 are sufficient for clearing the SCWCD exam

How to get radio button value in JSP?

2008-12-29T02:18:00.001-08:00

Usually we have a group of radio button which means that multiple radio buttons are present with the same name e.g.Somewhat related question may appear in the SCWCD exam asking for the correct code to retrieve values.This will be done as:request.getParameterValues() which returns an array of radio buttons against the name "t1". The array is String array and the code to display all the values is:

what is usebean standard action

2008-12-16T19:38:00.000-08:00

The SCWCD exam will definitely contain questions on jsp:useBean and its various attributes. So it is better to have a good hand at this standard action.When coding a JSP document (a JSP in XML format), the use of jsp:useBean becomes inevitable to create and use beans. For creating a bean, one has to use the jsp:usebean tag in the following formatwhich is equivalent tocom.test.TestClass test = new

sessions for SCWCD exam

2008-12-16T08:09:00.000-08:00

The purpose of this article is to include everything that can appear in the Sun Certified Web Component Developer (SCWCD) about sessions. Just read every line carefully and any question in SCWCD exam will be a cakewalk for you.The sessions are managed by a web server by using the session API of J2EE. The session concept is about recognizing the user. A user who has just logged in should not be

Context root path, servlet path and path info

2008-12-13T19:34:00.000-08:00

Let us understand context root path, resource path/ servlet path and path info:The root directory within the webapps directory (of servlet container) is known as the root directory of the web application. This directory also contains WEB-INF directory which contains class and library files. Every servlet request must contain the name of this directory and is known as context root path.The

session attributes

2008-12-08T07:26:00.000-08:00

The session object in Servlet and JSP model can be used to store objects which are needed till the time a user is logged in to the web application. As you may be aware that the time a user is using a web application (technically logged in) is known as the session. The objects that are stored programmatically to a session are known as session attributes. A session attribute can be any object

include directive vs include standard action

2008-11-20T08:31:00.000-08:00

The include directive is used to include the contest of a file statically whichc means the whole contents of another file will be included in the current file and then the current file will be compiled as a single unit.This is different from what happens in case of jsp:include standard action or c:import. In both cases, when a request from the client comes to the including page, the included

jsp:include vs c:import

2008-11-20T04:56:00.000-08:00

jsp:include and c:import both are used to include the contents of a file dynamically which means that container includes the output of files after evaluating them. Parameters can be passed in both the cases using jsp:param as shown below:As can be seen above, the first difference is the name of attribute used to specify the included file. The other subtle difference is that c:import can refer to

difference between simple and classic tags

2008-11-19T06:02:00.000-08:00

There are lot of differences between simple and classic tags. Here we try to understand the significant ones.For simple tags, extend SimpleTagSupport class. The dotage() method declares JspException as well as IOException.to send the body of simple tag to client:getJspBody.invoke(null)to send the body of simple tag to some writer object:getJspBody.invoke(java.io.writer wr)The getParent() method

Tag files

2008-11-19T05:18:00.000-08:00

When including files, one needs to either use include directive, include standard action or the include method of Request Dispatcher.For sending extra parameters to the included files in case of include standard action, param standard action is used which specifies the name and value of the parameter being passed.The problem is dual with this approach. Firstly, we need to use the predefined text

Design Patterns for SCWCD

2008-11-09T23:07:00.000-08:00

The exam will definitely have questions on design patterns but the following tips may be useful at work:1) Make your code cohesive: Each class/servlet defined in the application should be one specific task to do. That way, its easier to identify the class to be changed in case some changes are to be done in the application. For example: We need to look up the remote proxy’s when using JNDI and

What does getHeader, getParameter and getAttribute method return

2008-08-29T08:47:00.003-07:00

getHeader StringgetDateHeader longgetHeaders EnumerationgetIntHeader intgetParameter StringgetParameterNames EnumerationgetParameterValues String[]getParameterMap MapgetAttribute ObjectgetAttributeNames ObjectsetAttribute voidremoveAttribute void

Why getParameter methods in ServletRequest and headers in HttpServletRequest

2008-08-29T08:47:00.001-07:00

The Parameters are stored in the deployment descriptor file named web.xml. Since the underlying protocol can be anything other than HTTP, the getParameter methods have to be generic and protocol independent. This is the reason that the getParameter methods are present in ServletRequest class instead of HTTPServletRequest class.On the other hand, HTTP headers like method, cookies etc. are specific

Parametrs and Attributes

2008-08-29T08:46:00.001-07:00

Parameters are a kind of constants which are defined in the deployment descriptor file named web.xml. There are read only which means that there values can’t be changed by any servlet/JSP code. The parameters can be ServletConfig or ServletContext parameters. The ServletConfig parameters are defined for each servlet but the ServletContext parameters are shared among all servlets in a web

When is GET and POST used

2008-08-29T01:17:00.001-07:00

Clicking the hyperlink:GETSubmitting a form with method as GETGETSubmitting a form with no methodGETSubmitting a form with POST methodPOSTSubmitting a form by using JavaScript function which was called onclick()POSTEntering the URL and hitting the enterGETclick hereGET

Difference between HEAD and GET

2008-08-29T01:16:00.002-07:00

HEAD and GET requests are the same with the only difference that HEAD doesn’t include query string and only includes the response headers. Thus HEAD request is efficient when only response headers are to be retrieved.

Idempotent

2008-08-29T01:16:00.001-07:00

The client can send a request to the web server for different purposes like GET, POST, HEAD, TRACE etc. Out of all the HTTP methods, GET is the one which is idempotent. Being Idempotent means that GETgives the same result if it is invoked on the same form multiple times. Other methods may give same result in same cases but that behavior is not guaranteed for all requests.

Differences between GET and POST

2008-08-29T01:05:00.002-07:00

__________________POST__________________________GETData typeText or binaryTextForm elementsNot VisibleVisibleAmount of dataUnlimitedlimitedCachingNot cachedcached

Active and passive resources

2008-08-29T01:05:00.001-07:00

An active resource is the one which does some kind of processing or is designed to do some run time processing. e.g. servlets do some processing before the HTML content can be delivered Where as a passive resource is one which is returned to the client as it is. HTML files are the classic example of passive resources.

What is a web application?

2008-08-26T23:20:00.000-07:00

A web application is an application serving the clients using the web browser.The advantages of web application are:1) Follows client server technology and hence no business processing on client side2) Client can be a web browser which is available in each operating system3) Platform Independence4) Application can be deployed on the internet to reach more clientsBut a web application may need to

servlets or JSP

2008-08-26T07:31:00.000-07:00

When going through the Servlet and JSP API, a question comes to mind as what is better JSP or servlets. The servlets look more like Java and JSP more like HTML with those tags (custom and classic).Truly speaking, the project should be developed using both servlets and JSP. JSP’s are perfect for the view and servlets are perfect for the controller part of the MVC pattern. For those who want to

service methods in HTTPServlet class

2008-08-26T07:30:00.000-07:00

The HTTPServlet class implements the service() method so as to determine the method being used by the client to request the resource. And based on the method detected by the HTTPServlet class doXXX methods are called. The service method is called for each request sent by the client. If the service method is overridden by the servlet itself then it’s the responsibility of servlet coder to call

Why is GenericServlet class abstract?

2008-08-26T07:29:00.000-07:00

GenericServlet class is an abstract class because it doesn’t implement the service method and leaves that method to be implemented in protocol specific way by its subclasses. All other methods of the Servlet interface are implemented by the GenericServlet class. For the HTTP protocol, the HTTPServlet class provides the implementation of the service method.

What does getServletConfig() method do?

2008-08-26T07:27:00.000-07:00

The servlet container calls the init(ServletConfig) method of the GenericServlet class. The Servlet already creates an object of type ServletConfig and passes that object to the init(ServletConfig) method. Now it’s the responsibility of the init method to save a reference to the ServletConfig object so that the servlet can use this object to get the initialization parameters. The servlet can get

servlet container and servlet API

2008-08-22T01:46:00.001-07:00

The servlet API specifies the behavior of servlets in a standard way. There are some rules which each container must follow to Servlet API compliant. But there are some tasks whose implementation is left on to the servlet container.The servlet 2.5 specification is available for download at:http://jcp.org/aboutJava/communityprocess/mrel/jsr154/index.htmlThe API guarantees the behavior and