feat(lang): add java (#1132)

lua/lazyvim/plugins/extras/lang/java.lua

@@ -0,0 +1,74 @@
+return {
+  -- Add java to treesitter.
+  {
+    "nvim-treesitter/nvim-treesitter",
+    opts = function(_, opts)
+      if type(opts.ensure_installed) == "table" then
+        vim.list_extend(opts.ensure_installed, { "java" })
+      end
+    end,
+  },
+
+  -- Set up lsp with mfussenegger/nvim-jdtls instead of nvim-lspconfig.
+  {
+    "neovim/nvim-lspconfig",
+    dependencies = { "folke/which-key.nvim", "mfussenegger/nvim-jdtls" },
+    opts = {
+      -- make sure mason installs the server
+      servers = {
+        jdtls = {
+          -- stylua: ignore
+          keys = {
+            { "<leader>co", function() require("jdtls").organize_imports() end, desc = "Organize Imports", },
+            { "<leader>cR", function() require("jdtls").rename_file() end, desc = "Rename File", },
+            { "<leader>cxv", function() require("jdtls").extract_variable() end, desc = "Extract Variable", },
+            { "<leader>cxv", function() require("jdtls").extract_variable({ visual = true }) end, mode = "v", desc = "Extract Variable", },
+            { "<leader>cxc", function() require("jdtls").extract_constant() end, desc = "Extract Constant", },
+            { "<leader>cxc", function() require("jdtls").extract_constant({ visual = true }) end, mode = "v", desc = "Extract Constant", },
+            { "<leader>cxm", function() require("jdtls").extract_method({ visual = true }) end, mode = "v", desc = "Extract Method", },
+          },
+        },
+      },
+      setup = {
+        -- Override the default jdtls server startup to use nvim-jdtls.
+        jdtls = function()
+          -- The lspconfig configuration for jdtls contains two useful items:
+          -- 1. The list of filetypes on which to match.
+          -- 2. Custom method for finding the root for a java project.
+          local lsp_config = require("lspconfig.server_configurations.jdtls").default_config
+          local find_java_project_root = lsp_config.root_dir
+          local filetypes = lsp_config.filetypes
+
+          -- Attach jdtls for the proper filetypes (i.e. java).
+          -- Existing server will be reused if the root_dir matches.
+          vim.api.nvim_create_autocmd("FileType", {
+            group = vim.api.nvim_create_augroup("MyJdtls", { clear = true }),
+            pattern = filetypes,
+            callback = function()
+              local fname = vim.api.nvim_buf_get_name(0)
+              local root_dir = find_java_project_root(fname)
+              local project_name = root_dir and vim.fs.basename(root_dir)
+              local cmd = { "jdtls" }
+              if project_name then
+                local jdtls_cache_dir = vim.fs.joinpath(vim.fn.stdpath("cache"), "jdtls", project_name)
+                vim.list_extend(cmd, {
+                  "-configuration",
+                  vim.fs.joinpath(jdtls_cache_dir, "config"),
+                  "-data",
+                  vim.fs.joinpath(jdtls_cache_dir, "workspace"),
+                })
+              end
+              require("jdtls").start_or_attach({
+                cmd = cmd,
+                root_dir = root_dir,
+              })
+              require("which-key").register({ c = { x = { name = "Extract" } } }, { prefix = "<leader>" })
+            end,
+          })
+
+          return true -- avoid duplicate servers
+        end,
+      },
+    },
+  },
+}