The disadvantage sometimes of using DOM is that it uses to much resources in the sense of CPU and memory and for really huge files this method simply will not work in terms of performance. Parsing an XML document with DOM acquires the whole document to be loaded into memory before processing can be started. Via SAX only a small memory footprint is needed.
While searching on my local hard drive, I noticed that I, a long time ago in 2006, downloaded the zip file. Although of course, there is no support from Oracle for it anymore, at least I would expect it tbo unsupported because of the very outdated example, I made it available here for people who still can use it and are in need for an SAX loader example with which will able you to import / load very huge XML files into the database.
The OTN XML DB Sample had once the following available: