Yeah, best do the official Pivotal training then;
Spring Professional Certification
The courses tend to be delivered by actual spring developers, but it's probably best if you understand the fundamentals before the course. Unless the format has changed since the V4 course, then the schedule will be split between presentations and labs. The labs used STS (of course) so it is also useful to be familiar with this
IDE.
Other courses and options exist, and you no longer need to do the course before taking the exam.