Web.xml file is a configuration file in Java web application, it is used to define application wide and servlet/jsp wide settings.
It is a file referred by container on the server to identify Java resources available when requested by client.
Following is the list routine tags available in web.xml file.
<web-app> : It is the root tag of all the other tags in web.xml file
<servlet> : It is a sub tag of <web-app> tag, use to define servlets name and class, it has two more sub tags which are <servlet-name> and <servlet-class>
It is also used to declare parameter for the respective servlets, using <init-param> followed by two more sub tags, <param-nam> and <param-value>
It is use to describes a pattern used to resolve URLs. This tag is to be written inside <web-app> tag and outside of any <servlet> tag.
It is uses two more sub tags such as <servlet-name> and <url-pattern>
The optional <welcome-file-list> element contains an ordered list of welcome-file elements.
– Ravi Oza