index.html in Tomcat Server

Is it mandatory to have index.html while creating a new project?

If it is mandatory, how does the server recognize index.html?

Example:

when i give the following URL http://localhost:8080/servletExamples, the server takes me to index.html.

Thank You.

mithun gm, your name does not conform to the JavaRanch name policy.

Please take a moment to carefully read the policy and change your display name. Note that your name should consist of a first name, space and a second name. Two letters "gm" is not an acceptable second name.

Note that conforming to the name policy is not optional. If you do not change your name after multiple warnings, your account might be locked. You have already been warned more than once.

It is not mandatory.
This is also not a Tomcat specific issue.

There is a link to the servlet spec in my signature.
If you download a copy and search for <welcome-file-list>, you will see how to configure welcome pages in a Java web application.