# web.xml Visual Editor: General

Use to add, remove, and display the `web.xml` file's general information.

Overview of the Web Application Deployment Descriptor

Each web application has a deployment descriptor, which is an XML file that describes how the application should be deployed. The deployment descriptor tells the server about the components that make up the application. The elements of a deployment descriptor are listed below.

Element | Description
--- | ---
Context Parameters | These define the shared String constants that are used by the web application. Set these in the Context Parameters section.
Web Application Listeners | These list the listeners that the web application uses. Set these in the Web Application Listeners section.
Servlet Declarations | These list the servlets that the web application uses and provide initialization parameters. Set these in the Servlets section.
Servlet Mappings | These tell the servlet container which servlet to call for a given (context-relative) request URI or for a request URI pattern. Set these in the Servlets section.
Filter Declarations | These tell the servlet which filters to invoke for a servlet. Set these in the Filters section.
Welcome File List | This list specifies the file to use for the default welcome file, such as index.html. Set these in the Welcome Files section.
Error Page Declarations | These declare the JSP and HTML files that are to be used for handling specified error states and exceptions. Set these in the Error Pages section.
JSP Property Groups | These declare a set of properties defined for a group of JSP files within a web application. Note that this is supported from J2EE 1.4 onwards only. Set these in the JSP Property Groups section.
References | These declare logical names for different types of references used in the web application. Set these in the Environment Entries section, the Resource References section, the Resource Environment References section, the EJB References section, or the Message Destination References section.
Security | These declare the login configuration, security roles, and security constraints for the application.

You can define most of the contents of a `web.xml` file in the `web.xml` Visual Editor. For elements that cannot be defined in the editor, click Source at the top to view and edit the deployment descriptor's XML code.

The following general elements of the `web.xml` file can be defined in the General section.

Element | Description
--- | ---
Display Name | Specifies the file's display name, such as `Pizza Delivery Application, Version 1.13`.
Description | Specifies a description, such as `Deployment information for Version 1.13 of Pizza Delivery Application`.
Distributable | Specifies that all requests that are part of a session must be handled by one Java Virtual Machine (JVM) at a time. See section 7.7.2 of the Java Servlet Specification Version 2.4 for details.
Session Timeout | Specifies the default session timeout interval in minutes for all sessions created in the current web application. To set the session timeout interval for a specific session, use the `HttpSession.setMaxInactiveInterval(int interval)` method. By definition, if the timeout period for a session is set to `-1`, the session will never expire.

Related Topics

Developing Applications with NetBeans IDE,

Developing Applications with NetBeans IDE,

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