For normal development, having a working Eclipse workspace (preferably via Oomph) is of course sufficient, but should you ever need to build with maven, it's hard to find a command line that actually works (plus all the prerequisites like maven version, toolchains.xml etc. pp.).
Currently, when you look for information how to build JDT, you're lost in an infinite reference loop:
From https://github.com/eclipse-jdt/.github/blob/main/CONTRIBUTING.md:
That latter page simply links back to github.
For normal development, having a working Eclipse workspace (preferably via Oomph) is of course sufficient, but should you ever need to build with maven, it's hard to find a command line that actually works (plus all the prerequisites like maven version, toolchains.xml etc. pp.).