2. Currently domestic 200+
3 . OCA:3500+; OCP:7000+; ocm: 1.5w-2w
4.ocp certification has a question bank. You can take the exam if you think you are ok. However, oracle stipulates that ocp certification must participate in training, so it is not a big problem to participate in OCP testing when the technology reaches the intermediate level and then participate in the next training.
However, ocp exams must go to the original factory or WDP, and many affiliated students had better not go. It's better to go to WDP, which is cheap and has pre-test training, which is very helpful. The main reason is that the original factory is more expensive, which is no different from WDP. You can check WDP institutions in official website, Oracle Bone Inscriptions. Personally recommend CUUG. Everyone who takes the OCPCOCM exam goes here.
5.sap is also good.