Eclipse JDT LS & Gradle - Resource Exception "Invalid project description"

Question

Summary

I've been trying to get Eclipse's JDT LS (JLS) working with vim-lsp (in Neovim), but have been unsuccessful in synchronising the JLS with a Gradle project. I am, unfortunately, constrained to Windows.

The Problem

Using this configuration (commit #d1c7a25 at the time of posting), I cannot synchronise the JLS with a Gradle project "due to an error configuring Eclipse" because of an "invalid project description" (see log).

Trawling through Google and the GitHub issues of both the JLS and vim-lsp plugin has gotten me nowhere.

Remarks

I feel like it's most likely an issue with my configuration. If anyone has got this working with other LSP plugins aside from YouCompleteMe (such as CoC or LanguageClient) those setups are also welcome, but vim-lsp is preferred.

To reiterate, and just in case:

• Windows 10 Pro (v1803 build 17134.407)
• Neovim (v0.3.1) with plugin vim-lsp
• Gradle wrapper (v4.10.2)
• Eclipse JDT LS (v0.28.0 build 201811140630) [.tar.gz]
• using this configuration (originally #d1c7a25)

Thanks!

Answer 1

Figured it out.

The workspace directory for the JLS (specified by the command line argument -data) can't be nested under the project's own directory.

*bashes head on desk*