kickstart.nvim/lua/custom/plugins/jdtls.lua

return {
  'mfussenegger/nvim-jdtls',
  ft = { 'java' },
  config = function()
    vim.api.nvim_create_autocmd({ 'BufEnter', 'BufWinEnter' }, {
      group = vim.api.nvim_create_augroup('JonaJDTLS', {}),
      pattern = { '*.java' },
      callback = function()
        -- Based on https://github.com/Nawy/nvim-config-examples/blob/main/lsp-java/ftplugin/java.lua
        -- Java Language Server configuration.
        -- Locations:
        -- 'nvim/ftplugin/java.lua'.
        -- 'nvim/lang-servers/intellij-java-google-style.xml'

        local jdtls_ok, _ = pcall(require, 'jdtls')
        if not jdtls_ok then
          vim.notify 'JDTLS not found, install with `:LspInstall jdtls`'
          return
        end

        -- See `:help vim.lsp.start_client` for an overview of the supported `config` options.
        local jdtls_path = vim.fn.stdpath 'data' .. '/mason/packages/jdtls'
        local path_to_lsp_server = jdtls_path .. '/config_linux'
        local path_to_plugins = jdtls_path .. '/plugins/'
        local path_to_jar = path_to_plugins .. 'org.eclipse.equinox.launcher_1.6.800.v20240304-1850.jar'
        local lombok_path = jdtls_path .. '/lombok.jar'

        -- local root_markers = { ".git", "mvnw", "gradlew", "pom.xml", "build.gradle" }
        local root_markers = { '.git', 'mvnw', 'pom.xml', 'gradlew' }
        local root_dir = require('jdtls.setup').find_root(root_markers)
        if root_dir == '' then
          return
        end

        local project_name = vim.fn.fnamemodify(vim.fn.getcwd(), ':p:h:t')
        local workspace_dir = vim.fn.stdpath 'data' .. '/site/java/workspace-root/' .. project_name
        os.execute('mkdir -p ' .. workspace_dir)

        -- Main Config
        local config = {

          -- The command that starts the language server
          -- See: https://github.com/eclipse/eclipse.jdt.ls#running-from-the-command-line
          cmd = {
            'java',
            '-Declipse.application=org.eclipse.jdt.ls.core.id1',
            '-Dosgi.bundles.defaultStartLevel=4',
            '-Declipse.product=org.eclipse.jdt.ls.core.product',
            '-Dlog.protocol=true',
            '-Dlog.level=ALL',
            '-javaagent:' .. lombok_path,
            '-Xms1g',
            '--add-modules=ALL-SYSTEM',
            '--add-opens',
            'java.base/java.util=ALL-UNNAMED',
            '--add-opens',
            'java.base/java.lang=ALL-UNNAMED',

            '-jar',
            path_to_jar,
            '-configuration',
            path_to_lsp_server,
            '-data',
            workspace_dir,
          },

          -- This is the default if not provided, you can remove it. Or adjust as needed.
          -- One dedicated LSP server & client will be started per unique root_dir
          root_dir = root_dir,

          -- Here you can configure eclipse.jdt.ls specific settings
          -- See https://github.com/eclipse/eclipse.jdt.ls/wiki/Running-the-JAVA-LS-server-from-the-command-line#initialize-request
          -- for a list of options
          settings = {
            java = {
              home = '/usr/lib/jvm/jre-21-openjdk/',
              eclipse = {
                downloadSources = true,
              },
              configuration = {
                updateBuildConfiguration = 'interactive',
                runtimes = {
                  {
                    name = 'JavaSE-22',
                    path = '/usr/lib/jvm/jre-22-openjdk/',
                  },
                  {
                    name = 'JavaSE-21',
                    path = '/usr/lib/jvm/jre-21-openjdk/',
                  },
                  {
                    name = 'JavaSE-17',
                    path = '/usr/lib/jvm/jre-17-openjdk/',
                  },
                },
              },
              maven = {
                downloadSources = true,
              },
              implementationsCodeLens = {
                enabled = true,
              },
              referencesCodeLens = {
                enabled = true,
              },
              references = {
                includeDecompiledSources = true,
              },
              format = {
                enabled = true,
                settings = {
                  url = vim.fn.stdpath 'config' .. '/lang-servers/eclipse-java-google-style.xml',
                  profile = 'GoogleStyle',
                },
              },
            },
            signatureHelp = { enabled = true },
            completion = {
              favoriteStaticMembers = {
                'org.hamcrest.MatcherAssert.assertThat',
                'org.hamcrest.Matchers.*',
                'org.hamcrest.CoreMatchers.*',
                'org.junit.jupiter.api.Assertions.*',
                'java.util.Objects.requireNonNull',
                'java.util.Objects.requireNonNullElse',
                'org.mockito.Mockito.*',
              },
              importOrder = {
                'java',
                'javax',
                'com',
                'org',
              },
            },
            -- extendedClientCapabilities = extendedClientCapabilities,
            sources = {
              organizeImports = {
                starThreshold = 9999,
                staticStarThreshold = 9999,
              },
            },
            codeGeneration = {
              toString = {
                template = '${object.className}{${member.name()}=${member.value}, ${otherMembers}}',
              },
              useBlocks = true,
            },
          },

          flags = {
            allow_incremental_sync = true,
          },
          init_options = {
            bundles = {},
          },
        }

        -- config['on_attach'] = function(client, bufnr)
        --   require'keymaps'.map_java_keys(bufnr);
        --   require "lsp_signature".on_attach({
        --     bind = true, -- This is mandatory, otherwise border config won't get registered.
        --     floating_window_above_cur_line = false,
        --     padding = '',
        --     handler_opts = {
        --       border = "rounded"
        --     }
        --   }, bufnr)
        -- end

        -- vim.lsp.set_log_level 'trace'

        config['on_attach'] = require('jona.lsp').on_attach

        -- This starts a new client & server,
        -- or attaches to an existing client & server depending on the `root_dir`.
        require('jdtls').start_or_attach(config)
      end,
    })
  end,
}