fix(lsp-java): point jdtls to proper directory locations

Apparently, the per-project directory system I was using isn't supported
by the language server... even though there is absolutely no
documentation specifying that.

config.org

@@ -4219,15 +4219,26 @@ The =lsp-java= package provides LSP support using the standard Java language ser
   (setq lsp-java-jdt-ls-prefer-native-command t))
 (add-hook! java-mode
   (setq-local lsp-java-server-install-dir
-              (concat (+lsp-java-server-store-path) "/share/java/jdtls/")))
+              (f-slash (+lsp-java-server-store-path))))
 
-(defadvice! ~/lsp-java-ls-command ()
+;; The relative locations of the binary and jar file are different
-  "Configure `lsp-java' to work with Nix."
+;; on NixOS than on most other Linux distros
-  :override #'lsp-java--ls-command
+
-  (let ((root (or (doom-project-root) (f-join (getenv "XDG_DATA_HOME") "jdtls"))))
+(defadvice! ~/lsp-java-locate-server-jar (old-fn)
-    (list lsp-java-jdt-ls-command
+  :around #'lsp-java--locate-server-jar
-          "-configuration" (f-join root "config-linux")
+  (let ((lsp-java-server-install-dir
-          "-data" (f-join root "java-workspace"))))
+         (concat lsp-java-server-install-dir "share/java/jdtls/")))
+    (funcall old-fn)))
+#+end_src
+
+*** Project File Conflict
+
+Doom's standard library allows for an empty =.project= file to mark the root of a project directory. This is a decent idea, but unfortunately Gradle's project structure contains a file of that name that isn't necessarily at the root, and so this must be disabled to prevent Doom from breaking those projects.
+
+#+begin_src emacs-lisp
+(after! projectile
+  (setq projectile-project-root-files-bottom-up
+        (delete ".project" projectile-project-root-files-bottom-up)))
 #+end_src
 
 ** Language Servers