Java

info

You can enable the extra with the :LazyExtras command. Plugins marked as optional will only be configured if they are installed.

Alternatively, you can add it to your lazy.nvim imports

lua/config/lazy.lua

require("lazy").setup({
  spec = {
    { "LazyVim/LazyVim", import = "lazyvim.plugins" },
    { import = "lazyvim.plugins.extras.lang.java" },
    { import = "plugins" },
  },
})

Below you can find a list of included plugins and their default settings.

caution

You don't need to copy the default settings to your config. They are only shown here for reference.

nvim-treesitter

Add java to treesitter.

Options

opts = function(_, opts)
  opts.ensure_installed = opts.ensure_installed or {}
  vim.list_extend(opts.ensure_installed, { "java" })
end

Full Spec

{
  "nvim-treesitter/nvim-treesitter",
  opts = function(_, opts)
    opts.ensure_installed = opts.ensure_installed or {}
    vim.list_extend(opts.ensure_installed, { "java" })
  end,
}

mason.nvim

Options

opts = function(_, opts)
  opts.ensure_installed = opts.ensure_installed or {}
  vim.list_extend(opts.ensure_installed, { "java-test", "java-debug-adapter" })
end

Full Spec

{
  "williamboman/mason.nvim",
  opts = function(_, opts)
    opts.ensure_installed = opts.ensure_installed or {}
    vim.list_extend(opts.ensure_installed, { "java-test", "java-debug-adapter" })
  end,
}

nvim-lspconfig

Configure nvim-lspconfig to install the server automatically via mason, but defer actually starting it to our configuration of nvim-jtdls below.

Options

opts = {
  -- make sure mason installs the server
  servers = {
    jdtls = {},
  },
  setup = {
    jdtls = function()
      return true -- avoid duplicate servers
    end,
  },
}

Full Spec

{
  "neovim/nvim-lspconfig",
  opts = {
    -- make sure mason installs the server
    servers = {
      jdtls = {},
    },
    setup = {
      jdtls = function()
        return true -- avoid duplicate servers
      end,
    },
  },
}

nvim-jdtls

Set up nvim-jdtls to attach to java files.

Options

opts = function()
  return {
    -- How to find the root dir for a given filename. The default comes from
    -- lspconfig which provides a function specifically for java projects.
    root_dir = require("lspconfig.server_configurations.jdtls").default_config.root_dir,

    -- How to find the project name for a given root dir.
    project_name = function(root_dir)
      return root_dir and vim.fs.basename(root_dir)
    end,

    -- Where are the config and workspace dirs for a project?
    jdtls_config_dir = function(project_name)
      return vim.fn.stdpath("cache") .. "/jdtls/" .. project_name .. "/config"
    end,
    jdtls_workspace_dir = function(project_name)
      return vim.fn.stdpath("cache") .. "/jdtls/" .. project_name .. "/workspace"
    end,

    -- How to run jdtls. This can be overridden to a full java command-line
    -- if the Python wrapper script doesn't suffice.
    cmd = { vim.fn.exepath("jdtls") },
    full_cmd = function(opts)
      local fname = vim.api.nvim_buf_get_name(0)
      local root_dir = opts.root_dir(fname)
      local project_name = opts.project_name(root_dir)
      local cmd = vim.deepcopy(opts.cmd)
      if project_name then
        vim.list_extend(cmd, {
          "-configuration",
          opts.jdtls_config_dir(project_name),
          "-data",
          opts.jdtls_workspace_dir(project_name),
        })
      end
      return cmd
    end,

    -- These depend on nvim-dap, but can additionally be disabled by setting false here.
    dap = { hotcodereplace = "auto", config_overrides = {} },
    dap_main = {},
    test = true,
  }
end

Full Spec

{
  "mfussenegger/nvim-jdtls",
  dependencies = { "folke/which-key.nvim" },
  ft = java_filetypes,
  opts = function()
    return {
      -- How to find the root dir for a given filename. The default comes from
      -- lspconfig which provides a function specifically for java projects.
      root_dir = require("lspconfig.server_configurations.jdtls").default_config.root_dir,

      -- How to find the project name for a given root dir.
      project_name = function(root_dir)
        return root_dir and vim.fs.basename(root_dir)
      end,

      -- Where are the config and workspace dirs for a project?
      jdtls_config_dir = function(project_name)
        return vim.fn.stdpath("cache") .. "/jdtls/" .. project_name .. "/config"
      end,
      jdtls_workspace_dir = function(project_name)
        return vim.fn.stdpath("cache") .. "/jdtls/" .. project_name .. "/workspace"
      end,

      -- How to run jdtls. This can be overridden to a full java command-line
      -- if the Python wrapper script doesn't suffice.
      cmd = { vim.fn.exepath("jdtls") },
      full_cmd = function(opts)
        local fname = vim.api.nvim_buf_get_name(0)
        local root_dir = opts.root_dir(fname)
        local project_name = opts.project_name(root_dir)
        local cmd = vim.deepcopy(opts.cmd)
        if project_name then
          vim.list_extend(cmd, {
            "-configuration",
            opts.jdtls_config_dir(project_name),
            "-data",
            opts.jdtls_workspace_dir(project_name),
          })
        end
        return cmd
      end,

      -- These depend on nvim-dap, but can additionally be disabled by setting false here.
      dap = { hotcodereplace = "auto", config_overrides = {} },
      dap_main = {},
      test = true,
    }
  end,
  config = function()
    local opts = LazyVim.opts("nvim-jdtls") or {}

    -- Find the extra bundles that should be passed on the jdtls command-line
    -- if nvim-dap is enabled with java debug/test.
    local mason_registry = require("mason-registry")
    local bundles = {} ---@type string[]
    if opts.dap and LazyVim.has("nvim-dap") and mason_registry.is_installed("java-debug-adapter") then
      local java_dbg_pkg = mason_registry.get_package("java-debug-adapter")
      local java_dbg_path = java_dbg_pkg:get_install_path()
      local jar_patterns = {
        java_dbg_path .. "/extension/server/com.microsoft.java.debug.plugin-*.jar",
      }
      -- java-test also depends on java-debug-adapter.
      if opts.test and mason_registry.is_installed("java-test") then
        local java_test_pkg = mason_registry.get_package("java-test")
        local java_test_path = java_test_pkg:get_install_path()
        vim.list_extend(jar_patterns, {
          java_test_path .. "/extension/server/*.jar",
        })
      end
      for _, jar_pattern in ipairs(jar_patterns) do
        for _, bundle in ipairs(vim.split(vim.fn.glob(jar_pattern), "\n")) do
          table.insert(bundles, bundle)
        end
      end
    end

    local function attach_jdtls()
      local fname = vim.api.nvim_buf_get_name(0)

      -- Configuration can be augmented and overridden by opts.jdtls
      local config = extend_or_override({
        cmd = opts.full_cmd(opts),
        root_dir = opts.root_dir(fname),
        init_options = {
          bundles = bundles,
        },
        -- enable CMP capabilities
        capabilities = LazyVim.has("cmp-nvim-lsp") and require("cmp_nvim_lsp").default_capabilities() or nil,
      }, opts.jdtls)

      -- Existing server will be reused if the root_dir matches.
      require("jdtls").start_or_attach(config)
      -- not need to require("jdtls.setup").add_commands(), start automatically adds commands
    end

    -- Attach the jdtls for each java buffer. HOWEVER, this plugin loads
    -- depending on filetype, so this autocmd doesn't run for the first file.
    -- For that, we call directly below.
    vim.api.nvim_create_autocmd("FileType", {
      pattern = java_filetypes,
      callback = attach_jdtls,
    })

    -- Setup keymap and dap after the lsp is fully attached.
    -- https://github.com/mfussenegger/nvim-jdtls#nvim-dap-configuration
    -- https://neovim.io/doc/user/lsp.html#LspAttach
    vim.api.nvim_create_autocmd("LspAttach", {
      callback = function(args)
        local client = vim.lsp.get_client_by_id(args.data.client_id)
        if client and client.name == "jdtls" then
          local wk = require("which-key")
          wk.register({
            ["<leader>cx"] = { name = "+extract" },
            ["<leader>cxv"] = { require("jdtls").extract_variable_all, "Extract Variable" },
            ["<leader>cxc"] = { require("jdtls").extract_constant, "Extract Constant" },
            ["gs"] = { require("jdtls").super_implementation, "Goto Super" },
            ["gS"] = { require("jdtls.tests").goto_subjects, "Goto Subjects" },
            ["<leader>co"] = { require("jdtls").organize_imports, "Organize Imports" },
          }, { mode = "n", buffer = args.buf })
          wk.register({
            ["<leader>c"] = { name = "+code" },
            ["<leader>cx"] = { name = "+extract" },
            ["<leader>cxm"] = {
              [[<ESC><CMD>lua require('jdtls').extract_method(true)<CR>]],
              "Extract Method",
            },
            ["<leader>cxv"] = {
              [[<ESC><CMD>lua require('jdtls').extract_variable_all(true)<CR>]],
              "Extract Variable",
            },
            ["<leader>cxc"] = {
              [[<ESC><CMD>lua require('jdtls').extract_constant(true)<CR>]],
              "Extract Constant",
            },
          }, { mode = "v", buffer = args.buf })

          if opts.dap and LazyVim.has("nvim-dap") and mason_registry.is_installed("java-debug-adapter") then
            -- custom init for Java debugger
            require("jdtls").setup_dap(opts.dap)
            require("jdtls.dap").setup_dap_main_class_configs(opts.dap_main)

            -- Java Test require Java debugger to work
            if opts.test and mason_registry.is_installed("java-test") then
              -- custom keymaps for Java test runner (not yet compatible with neotest)
              wk.register({
                ["<leader>t"] = { name = "+test" },
                ["<leader>tt"] = { require("jdtls.dap").test_class, "Run All Test" },
                ["<leader>tr"] = { require("jdtls.dap").test_nearest_method, "Run Nearest Test" },
                ["<leader>tT"] = { require("jdtls.dap").pick_test, "Run Test" },
              }, { mode = "n", buffer = args.buf })
            end
          end

          -- User can set additional keymaps in opts.on_attach
          if opts.on_attach then
            opts.on_attach(args)
          end
        end
      end,
    })

    -- Avoid race condition by calling attach the first time, since the autocmd won't fire.
    attach_jdtls()
  end,
}

which-key.nvim

Options

opts = nil

Full Spec

{ "folke/which-key.nvim" }

nvim-dap (optional)

Ensure java debugger and test packages are installed.

Options

opts = nil

Full Spec

{
  "mfussenegger/nvim-dap",
  optional = true,
  dependencies = {
    {
      "williamboman/mason.nvim",
      opts = function(_, opts)
        opts.ensure_installed = opts.ensure_installed or {}
        vim.list_extend(opts.ensure_installed, { "java-test", "java-debug-adapter" })
      end,
    },
  },
}