ColdFusion error types

Before you can effectively manage ColdFusion errors, you must understand how ColdFusion classifies and handles them. ColdFusion categorizes errors as detailed in the following table:

Type Description

Type	Description
Exception	An error that prevents normal processing from continuing. All ColdFusion exceptions are, at their root, Java exceptions.
Missing template	An HTTP request for a ColdFusion page that cannot be found. Generated if a browser requests a ColdFusion page that does not exist. Missing template errors are different from missing include exceptions, which result from `cfinclude` tags or custom tag calls that cannot find their targets.
Form field data validation	Server-side form field validation errors are a special kind of ColdFusion MX exception. You specify server-side form validation by using `cfform` attributes or hidden HTML form fields. All other types of server-side validation, such as the `cfparam` tag generate runtime exceptions. For more information on validating form fields see Validating Data. ColdFusion includes a built-in error page for server-side form field validation errors, and the `cferror` tag includes a `type` attribute that lets you handle these errors in a custom error page, but if you use `onError` processing in Application.cfc, or try/catch error handling, the error appears as an Application exception. For more information on handling Form field validation in Application.cfc see Handling server-side validation errors in the onError method.

Exception

An error that prevents normal processing from continuing. All ColdFusion exceptions are, at their root, Java exceptions.

Missing template

An HTTP request for a ColdFusion page that cannot be found. Generated if a browser requests a ColdFusion page that does not exist.

Missing template errors are different from missing include exceptions, which result from cfinclude tags or custom tag calls that cannot find their targets.

Form field data validation

Server-side form field validation errors are a special kind of ColdFusion MX exception. You specify server-side form validation by using cfform attributes or hidden HTML form fields. All other types of server-side validation, such as the cfparam tag generate runtime exceptions. For more information on validating form fields see Validating Data.

ColdFusion includes a built-in error page for server-side form field validation errors, and the cferror tag includes a type attribute that lets you handle these errors in a custom error page, but if you use onError processing in Application.cfc, or try/catch error handling, the error appears as an Application exception. For more information on handling Form field validation in Application.cfc see Handling server-side validation errors in the onError method.

Note: The onSubmit and onBlur form field validation techniques use JavaScript or Macromedia Flash validation on the client browser; this chapter does not discuss client-side validation errors.

Most ColdFusion errors are exceptions. The following sections describe them in detail.

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