The installer and the demo environment are available on the Oracle Data Integrator
Downloads page on Oracle Technology Network (OTN).
To download the installer and the demo environment:
Go to the Oracle Data Integrator Downloads page on OTN at
Main page has only 12c download.
You can find it on this page : http://www.oracle.com/technetwork/middleware/data-integrator/learnmore/index.html
Direct link : http://www.oracle.com/technetwork/middleware/data-integrator/overview/oracledi-demo-168262.zip