I applied through a recruiter. I interviewed at Oracle (Redwood City, CA) in Oct 2012
Interview
I was initially contacted by the recruiter and they asked me to fly to the HQ in Redwood Shores. I talked to five different teams. Each interview took about 1.5 hours. The interview style vary from team to team and from person to person. Overall, the experience was great and I enjoyed the day I spent at Oracle HQ in Redwood Shores.
I applied through college or university. I interviewed at Oracle (Redwood City, CA) in Nov 2009
Interview
Interview with Oracle through college recruiting 4 years ago. If you graduate from their list of target school, it is easy to get an onsite. Before the onsite, the recruiter sent you a list of groups that are interested in interviewing you. You can pick 6-7 to interview with. It a whole day process. Each team you usually talk to their hire manager and one developer. Not much technical questions with the manager. The developer would ask some technical questions.
Directly invited by HR via email and scheduled an on-site three weeks later. The whole interview process works fine and as a potential employee, you would have more than enough opportunities to receive an offer from the company. I think they maintain a relatively strict invitation bar to limit school from which the candidate would graduate.