LunarVim/lua/nv-lspinstall/init.lua

-- 1. get the config for this server from nvim-lspconfig and adjust the cmd path.
--    relative paths are allowed, lspinstall automatically adjusts the cmd and cmd_cwd for us!
local config = require'lspconfig'.jdtls.document_config
require'lspconfig/configs'.jdtls = nil -- important, unset the loaded config again
-- config.default_config.cmd[1] = "./node_modules/.bin/bash-language-server"

-- 2. extend the config with an install_script and (optionally) uninstall_script
require'lspinstall/servers'.jdtls = vim.tbl_extend('error', config, {
    -- lspinstall will automatically create/delete the install directory for every server
    install_script = [[
      git clone https://github.com/eclipse/eclipse.jdt.ls.git
      cd eclipse.jdt.ls
      ./mvnw clean verify
  ]],
    uninstall_script = nil -- can be omitted
})

require'lspinstall'.setup()