This document details the internals of how the sqoop-server works.
contextInitialized callback to initialize all the related code.
<!-- Listeners -->
<listener>
<listener-class>org.apache.sqoop.server.ServerInitializer</listener-class>
</listener>
3. SqoopServer.initialize() is the main entry point.
4. There are a bunch of servlets in web.xml : https://github.com/apache/sqoop/blob/sqoop2/server/src/main/webapp/WEB-INF/web.xml
They receive the requests and process it. Each Servlet has its corresponding handler class that handles the request for that servlet. It then internally calls the internal sqoop core/ common code.
All the rest APIs supported are documented here: http://sqoop.apache.org/docs/1.99.4/RESTAPI.html#id1
There is also the Sqoop-client that used to invoke the Sqoop-server methods via the jersey REST client, Recently it was switched to Hadoop-auth for adding Kerberos support that are documented herehttps://cwiki.apache.org/confluence/display/SQOOP/Security+Guide+On+Sqoop+2