java-lsp: fix small bug

nix/neovim-overlay.nix

@@ -99,7 +99,7 @@ with final.pkgs.lib; let
     # language servers, etc.
     lua-language-server
     clang-tools # provides clangd which is a c/c++ lsp
-    gcc
+    java-language-server
     nil # nix LSP
 
     # autoformatters
@@ -109,6 +109,7 @@ with final.pkgs.lib; let
 
     # misc
     nodejs # eww
+    gcc
   ];
 in {
   # This is the neovim derivation

nvim/ftplugin/java.lua

@@ -0,0 +1,16 @@
+-- Exit if the language server isn't available
+if vim.fn.executable('java-language-server') ~= 1 then
+  return
+end
+
+local root_files = {
+  '.git',
+  'Main.java',
+}
+
+vim.lsp.start {
+  name = 'java_language_server',
+  cmd = { 'java-language-server' },
+  root_dir = vim.fs.dirname(vim.fs.find(root_files, { upward = true })[1]),
+  capabilities = require('user.lsp').make_client_capabilities(),
+}