nixos: gen 21 @ lilac — 2026-09-01 11:37 26.05.20260814.02e0898 (Yarara) -----

home/programs/nvim.nix

@@ -7,11 +7,6 @@
     vimAlias = true;
     defaultEditor = true;
 
-    extraPackages = with pkgs; [
-      jdtls
-      jdk
-    ];
-
     initLua = ''
       vim.opt.number = true
       vim.opt.relativenumber = true
@@ -91,30 +86,94 @@
         },
       })
 
-      local lspconfig = require('lspconfig')
+      -- Java indentation must match Eclipse's formatter, not your 2-space default.
+      vim.api.nvim_create_autocmd("FileType", {
+        pattern = "java",
+        callback = function()
+          vim.bo.expandtab = false
+          vim.bo.tabstop = 4
+          vim.bo.shiftwidth = 4
+          vim.bo.softtabstop = 4
+        end,
+      })
 
-      -- Common keymaps to run when the Eclipse LSP attaches to a Java buffer
-      local on_attach = function(client, bufnr)
-        local opts = { buffer = bufnr, silent = true }
+      local cmp = require("cmp")
+      local luasnip = require("luasnip")
+      cmp.setup({
+        snippet = { expand = function(a) luasnip.lsp_expand(a.body) end },
+        mapping = cmp.mapping.preset.insert({
+          ["<C-Space>"] = cmp.mapping.complete(),
+          ["<CR>"] = cmp.mapping.confirm({ select = false }),
+          ["<C-n>"] = cmp.mapping.select_next_item(),
+          ["<C-p>"] = cmp.mapping.select_prev_item(),
+        }),
+        sources = {
+          { name = "nvim_lsp" },
+          { name = "luasnip" },
+          { name = "buffer" },
+          { name = "path" },
+        },
+      })
 
-        -- Eclipse IDE core features mapped to Neovim actions
-        vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, opts)
-        vim.keymap.set('n', 'gd', vim.lsp.buf.definition, opts)
-        vim.keymap.set('n', 'K', vim.lsp.buf.hover, opts)
-        vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, opts)
-        vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, opts)
-        vim.keymap.set('n', '<leader>rn', vim.lsp.buf.rename, opts)
-        vim.keymap.set('n', '<leader>ca', vim.lsp.buf.code_action, opts)
-        vim.keymap.set('n', 'gr', vim.lsp.buf.references, opts)
-        vim.keymap.set('n', '<leader>f', function() vim.lsp.buf.format { async = true } end, opts)
+      local capabilities = require("cmp_nvim_lsp").default_capabilities()
+
+      -- .project and .classpath come first so a repo containing several
+      -- assignments resolves to the assignment, not the repo root.
+      local root_markers = { ".project", ".classpath", "pom.xml", "build.gradle", ".git" }
+
+      local function start_jdtls()
+        local jdtls = require("jdtls")
+        local root_dir = require("jdtls.setup").find_root(root_markers)
+        if not root_dir or root_dir == "" then return end
+
+        local project_name = vim.fn.fnamemodify(root_dir, ":p:h:t")
+        local workspace = vim.fn.stdpath("cache") .. "/jdtls-workspaces/" .. project_name
+
+        local java_settings = {
+          configuration = {
+            updateBuildConfiguration = "interactive",
+            runtimes = {
+              { name = "JavaSE-21", path = os.getenv("JAVA_HOME"), default = true },
+            },
+          },
+          -- Keep a stray pom.xml from overriding the Eclipse project model.
+          -- Flip these on if a course actually requires Maven or Gradle.
+          import = {
+            maven = { enabled = false },
+            gradle = { enabled = false },
+          },
+          signatureHelp = { enabled = true },
+          eclipse = { downloadSources = true },
+        }
+
+        -- If the repo carries an exported Eclipse formatter profile, use it verbatim.
+        local formatter = root_dir .. "/.settings/eclipse-formatter.xml"
+        if vim.uv.fs_stat(formatter) then
+          java_settings.format = { settings = { url = formatter } }
+        end
+
+        jdtls.start_or_attach({
+          cmd = { "jdtls", "-data", workspace },
+          root_dir = root_dir,
+          capabilities = capabilities,
+          settings = { java = java_settings },
+          init_options = { bundles = {} },
+          on_attach = function(_, bufnr)
+            local map = function(k, f) vim.keymap.set("n", k, f, { buffer = bufnr, silent = true }) end
+            map("gd", vim.lsp.buf.definition)
+            map("gr", vim.lsp.buf.references)
+            map("K", vim.lsp.buf.hover)
+            map("<leader>rn", vim.lsp.buf.rename)
+            map("<leader>ca", vim.lsp.buf.code_action)
+            map("<leader>f", function() vim.lsp.buf.format({ async = true }) end)
+            map("<leader>oi", require("jdtls").organize_imports)
+          end,
+        })
       end
 
-      -- Initialize the Eclipse JDTLS Server configuration
-      -- NixOS patches 'jdtls' wrapper script automatically to point to the correct binary paths
-      lspconfig.jdtls.setup({
-        on_attach = on_attach,
-        cmd = { "jdtls" },
-        root_dir = lspconfig.util.root_pattern(".git", "pom.xml", "build.gradle"),
+      vim.api.nvim_create_autocmd("FileType", {
+        pattern = "java",
+        callback = start_jdtls,
       })
     '';
 
@@ -126,7 +185,15 @@
       { plugin = lualine-nvim; }
       { plugin = neocord; }
       { plugin = gitsigns-nvim; }
-      { plugin = nvim-lspconfig; }
+
+      { plugin = nvim-jdtls; }
+      { plugin = nvim-cmp; }
+      { plugin = cmp-nvim-lsp; }
+      { plugin = cmp-buffer; }
+      { plugin = cmp-path; }
+      { plugin = luasnip; }
+      { plugin = cmp_luasnip; }
+      { plugin = (nvim-treesitter.withPlugins (p: [ p.java p.xml p.nix p.lua ])); }
     ];
   };
 }

system/packages.nix

@@ -22,7 +22,10 @@
       ];
     })
     google-chrome
+    google-java-format
     gnupg
+    jdk
+    jdt-language-server
     jq
     keepassxc
     lan-mouse