Getting diagnostics about all files in a project not only the ones open in the editor?

[HaraldKi]

In the eclipse UI one can see all compilation diagnostics, whether a file is open in the editor or not/

Using Emacs' Eglot, there are only the diagnostics for open files. According to the lsp documentation, it is up to the server which diagnostics are published when, so my hunch is that it is not directly an Eglot problem.Therefore the question:

Does eclipse.jdt.ls in principle provide diagnostics for all files and if yes, what do I need to do to get it. Is there some configuration option I am missing?

I am working with a gradle project, if that makes a difference.