Coldfusion Interview Questions

ColdFusion is a commercial rapid development framework by Adobe. It was developed by J. J. Allaire in 1995 for providing an easier way to connect static Html Pages to database. It is completely written in Java programming language that provides expressive and powerful web development.

The reactor in ColdFusion is used to monitor the production server continuously. It will monitor, diagnose, and analyze application and server issued. It has been implemented as a java agent and released first in 2005. Since its release, the reactor is popular among some of the largest organizations in the world.

This proprietary performance monitor is available for all the major operating systems such as Linux, Mac OS, Windows, and UNIX.

You can go to the caching page in the server settings to clear the cache in ColdFusion. You can click the "clear template cache now" button to clear the cache. You can also choose the "clear folder specific template cache" to clear the cache from individual folders.

The different data types in the Coldfusion are,

Integers - they are used to store whole numbers.

Real Numbers - they are the floating-point numbers.

Strings - They are used to store a sequence of letters, symbols, or characters.

Booleans - They are "true" or "false" values.

Date-time - They are the data or time values.

Lists - It consists of multiple strings separated by a delimiter.

Arrays - It is a complex data-type. Some other types present in Coldfusion are Structure, queries, binary, and object.

The application.cfc file is used to set the global variables in the Coldfusion.

The request variables in the Coldfusion is used to store processing data of the page request. The data stored in the request variables can be easily passed to the nested tags, and then processed.

//example
<CFSET Request.field_name1 = "value">
<CFSET Request.field_name2 = "value">
<CFSET Request.field_name3 = "value">

The different types of scope available in the ColdFusion are,

Variables - Variables are available only during the execution of the template.

URL - URL variables are available only for the current request.

Form - Form variables are only available for the current request.

CGI - CGI variables are available only for the current request.

Query - The data stored in the pointer are available for the current request.

Server - The server scope is available across all the requests until the server shuts down.

Application - The application variables are used by all the connected clients for current applications.

Session - The session scope is available only to the current session and can persist until the termination of the server or application.

Request - The data in this scope is available to the current request.

Arguments - This scope is mutually exclusive with the local function scope.

Attributes - This scope is available during the lifespan of the custom tag.

Local - This scope is mutually exclusive to the argument scope.

The default time-out for the session variable in Coldfusion is 20 minutes but you can change this time on the memory variable page in the server settings present in the Coldfusion administrator.

There are three different types of error present in the Coldfusion,

Exception error - It occurs when an error stops the request from completion of its process.

Missing Template - This error occurs when an HTTP request for a page cannot be found.

Form Field Data Validation - This error occurs when server-side form validation fails.

But the most common type of error you get with Coldfusion is the Exception type error.

The onsessionstart function in Coldfusion is used to initialize the session scope data or session-specific application scope variables. This method can also access the variable scope if the application.cfc file has an onRequest method. It doesn’t return any value and runs when a session starts.

//Syntax
<cffunction name="onSessionStart" returnType="void">
...
</cffunction>

Flash Form is generated by the Coldfusion automatically from the CFML code, using the tag. It is like an HTML form but has a flash format and runs on the flash player enabled web browsers. It is used to enhance the user experience with features such as accordion-style, multiple-tab form panes and positioning of elements automatically.

Below are a few advantages of using ColdFusion are

• It is easy to use.
• Provides high performance at runtime
• Easy to Integrate
• Inbuilt user interface elements
• Supports .Net objects
• Integration with other tools

ColdFusion is mainly used for creating data-driven websites however you can it for creating REST web services.

Application.cfm contains a set of codes that we want to execute on every page of the app. Whenever a request for any page is received by Coldfusion application then it searches the page directory for Application.cfm.

Application.cfm file can be used for setting application name, enabling and disabling sessions, Set timeouts, storing client variables, defining application global settings and much more.

A component in ColdFusion is an independent file that contains data and functions. You can think of ColdFusion Components (CFCs) similar to Classes in other object-oriented programming languages.

All components in ColdFusion are wrapped into <cfcomponent> tag that contains one or more <cffunction>s tags.

CFX tags in Coldfusion are custom tags written in Java or C++ programming language to extend the functionality of the ColdFusion framework.