ENEL, the leading company in Italy and the second in Europe among those supplying electricity.
I worked on several projects including SEREM GAS and SEMPRE Elettrico

My role was initially as Senior Java and Oracle developer and, after one year, also as Team leader coordinating a group of three people

In both projects the architecture was identical: JSP and Struts as View and Controller, and DAO layer as Persistence

As both projects treated huge quantity of data, there was a very important work in sql optimization,
So, optimizing query with indexes, partition, explain plain (thanks a lot TOAD) and executing statistic.
Also, many business functions were inside directly the DB by sql functions and procedure, called many time also by Java batch

In these projects I experienced a lot in oracle technologies

The source code versioning was implemented by SVN and the build tool was Ant