Coldfusion Interview questions and answers

1.What is CFScheduler?
It provides a programmatic interface to the ColdFusion scheduling engine. It can run a CFML page at scheduled intervals, with the option to write the page output to a static HTML page. This feature enables you to schedule pages that publish data, such as reports, without waiting while a database transaction is performed to populate the page.

2. What is Web Server?

A computer that delivers (serves up) Web pages. Every Web server has an IP address and possibly a domain name. For example, if you enter the URL http://www.domainname.com/index.html in your browser, this sends a request to the server whose domain name is domainname.com. The server then fetches the page named index.html and sends it to your browser.
Any computer can be turned into a Web server by installing server software and connecting the machine to the Internet. There are many Web server software applications, including public domain software from NCSA and Apache, and commercial packages from Microsoft, Netscape and others.

3. What is Application Server?

A server that exposes business logic to client applications through various protocols including HTTP, HTTPS, IIOS/SSL. Eg: Sun Java Application server, weblogic server

It takes care of important issues like Transaction Management, Security, Database Connection Pooling, Clustering, Scalability,session management,load balancing,thread management and Messaging etc. A web server cannot provide these.

4. How can you communicate with web server (Apache or IIS) from Coldfusion?

Cold Fusion is an example of a Common Gateway Interface application. The Common Gateway Interface is a mechanism to allow Web servers, which are designed to serve static documents, to receive dynamic output from programs and serve it as if it were static data.

1. When a browser sends a request for a Cold Fusion template to a Web server, several things must happen. First, the Web server recognizes the information from the browser as a request for CGI output.
2.If the request was initiated from a form, the server has to write the form field information to some area in storage that is accessible to other programs on the machine. Usually, this is done by using STDOUT data streams. The WinCGI interface, which can be used by WebSite and other servers, writes the form data to INI-style files on disk, which are then opened and read by the CGI application.
3.The CGI program requests data from the data source, which is returned in step
4. The CGI program formats the data as HTML output, returning this output to the server in step
5. The server receives this output, performs any further server-side processing necessary, and then sends it to the browser.

Cold Fusion defaults to using server API modules instead of CGI to communicate between the Web Server and ColdFusion Application Server.

5. What are the advantages of Cold fusion?

Simplified Installation and Migration
All Operating System (OS) Support
All Database support
Faster Development & Easy to Learn
Improved & support for all Protocols
access to all the J2EE libraries
Integration with Other adobe Products (Flex, Flash, PDF..)

11. What is “Application.cfm”?
When ColdFusion receives a request for an application page, it searches the page's directory for a file named Application.cfm. If one exists, the Application.cfm code is logically included at the beginning of that application page.
If your application runs on a UNIX platform, which is case-sensitive, you must spell Application.cfm with an initial capital letter.

12. Can we have multiple “Application.cfm” file in an Application?

Yes. If the application page directory does not have an Application.cfm page, ColdFusion searches up the directory tree until it finds an Application.cfm page. If several directories in the directory tree have an Application.cfm page, ColdFusion uses the first page it finds. If the Application.cfm page is present in the directory tree (and has the required permissions set), you cannot prevent ColdFusion from including it.
ColdFusion processes only one Application.cfm page for each request. If a ColdFusion page has a cfinclude tag pointing to an additional ColdFusion page, ColdFusion does not search for an Application.cfm page when it includes the additional page.

14. Scenario: You have “Application.cfm” in your Root directory, another “Application.cfm” file in child directory. If you are running a cold fusion page from child directory what will happen? Which one (Application.cfm) will execute? Whether both or?
You already have the answer for this question in the 12th question. :)
15. What is cfapplication tag?
It defines the scope of a ColdFusion application; enables and disables storage of Client variables; specifies the Client variable storage mechanism; enables Session variables; and sets Application variable time-outs.
17. How can you set the Client Management?
We can enable & disable client management as well as we can configure How & Where client variables need to be store
1. In the Application.cfc initialization code
This.clientmanagement="True" / "false"
This.clientStorage="[Ur_datasource_name]" / "registry" / "cookie"
2. In appliation.cfm using tag attributes
clientManagement="yes" / "no"
clientStorage="[Ur_datasource_name]" / "registry" / "cookie"
[Ur_datasource_name] - Stored in ODBC or native data source. You must create storage repository in the Administrator.
registry - Stored in the system registry.
cookie - Stored on client computer in a cookie. Scalable. If client disables cookies in the browser, client variables do not work.