Some people claim it is relatively hard to contribute code to an Eclipse platform project (without Oomph). But even without additional tooling is actually very easy to setup the necessary configuration to contribute to Eclipse platform UI.
Here are the necessary steps:
If I put these instructions on A4 paper, they take 5 pages, including lots of screenshots.
Based on our experience during Eclipse Hamburg Hackathons, this setup usually takes less then 10 minutes for an unexperienced users, plus the time you need to clone the Git repo.
This setup used to be more complex in the past but we constantly work on making it simpler. Also a big thanks to the Eclipse Git tooling project which makes the configuration as seamless as possible.