It is used to generate javadocs for a package.
/**
* Domain classes used to produce .....
* <p>
* These classes contain the ......
* </p>
*
* @since 1.0
* @author somebody
* @version 1.0
*/
package com.domain;
Will generate package info for com.domain package:
Example result: https://docs.oracle.com/javase/7/docs/api/java/awt/package-summary.html