nvim-jdtls

Extensions for the built-in Language Server Protocol support in Neovim (>= 0.5) for eclipse.jdt.ls.

Warning: This is early state. Neovim 0.5 hasn't been released yet, so APIs can change and things may break.

Extensions

• Command to organize imports
• Open class file contents
• Code action extensions (java.apply.workspaceEdit).
• toString generation.
• hashCode and equals generation.
• javap command to show bytecode of current file
• Integration with nvim-dap

Installation

• Requires Neovim HEAD/nightly
• nvim-jdtls is a plugin. Install it like any other Vim plugin.
• Call :packadd nvim-jdtls if you install nvim-jdtls to 'packpath'.

Usage

nvim-jdtls doesn't contain logic to spawn a LSP client for eclipse.jdt.ls, see :help lsp for information on how to launch a LSP client. To make use of all the functionality nvim-jdtls provides, you need to override some of the lsp callbacks, set some extra capabilities and set a couple of initialization options.

The callbacks:

  local jdtls = require 'jdtls'
  vim.lsp.callbacks['workspace/applyEdit'] = jdtls.workspace_apply_edit,

Additional capabilities:

local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.codeAction = {
  dynamicRegistration = false;
  codeActionLiteralSupport = {
    codeActionKind = {
      valueSet = {
        "source.generate.toString",
        "source.generate.hashCodeEquals"
      };
    };
  };
}
capabilities.workspace = {
  applyEdit = true;
}

Initialization options:

config['init_options'] = {
  extendedClientCapabilities = {
    classFileContentsSupport = true;
    generateToStringPromptSupport = true;
    hashCodeEqualsPromptSupport = true;
  };
}

You may also want to create mappings for the code action command and to organize imports:

nnoremap <A-CR> <Cmd>lua require'jdtls'.code_action()<CR>
nnoremap <A-o> <Cmd>lua require'jdtls'.organize_imports()<CR>
nnoremap <leader>df <Cmd>lua require'jdtls'.test_class()<CR>
nnoremap <leader>dn <Cmd>lua require'jdtls'.test_nearest_method()<CR>

nvim-dap

nvim-jdtls provides integration with nvim-dap.

For this to work, eclipse.jdt.ls needs to load the java-debug extension. To do so, clone java-debug and run ./mvnw clean install in the cloned directory, then extend the initializationOptions with which you start eclipse.jdt.ls:

config['init_options'] = {
  bundles = {
    vim.fn.glob("path/to/java-debug/com.microsoft.java.debug.plugin/target/com.microsoft.java.debug.plugin-*.jar")
  };
}

You also need to call require('jdtls').setup_dap() to have it register a java adapter for nvim-dap and to create configurations for all discovered main classes:

config['on_attach'] = function(client, bufnr)
  require('jdtls').setup_dap()
end

Furthermore, nvim-jdtls supports running and debugging tests. For this to work the bundles from vscode-java-test need to be installed:

• Clone the repo
• Run npm install
• Run npm run build-plugin
• Extend the bundles:

local bundles = {
  vim.fn.glob("path/to/java-debug/com.microsoft.java.debug.plugin/target/com.microsoft.java.debug.plugin-*.jar"),
};
vim.list_extend(bundles, vim.split(vim.fn.glob("/path/to/microsoft/vscode-java-test/server/*.jar"), "\n"))
config['init_options'] = {
  bundles = bundles;
}