Yes, you can start the Bootcamp as a complete beginner.
The Full Stack Java Bootcamp is designed to teach you everything you need to know to get a job as a full-stack Java programmer, even if you know nothing. We've built our educational approach on helping people with zero experience to learn how to code. So you can start as a pure beginner with no prior knowledge.
We have found that students do find it helpful to have a basic level of understanding of how programming works. For instance, knowing general concepts about variables, IF statements, loops, and perhaps data structure is very helpful. However, we will be covering all of these topics in the first couple of weeks of the Bootcamp.