jc.nvim

jc.nvim – successor of vim-javacomplete2 which use neovim's built-in LSP client and Eclipse JDT Language Server.

Read my blog post about it.

Main goal of this project is to migrate functionallty of jc2.

In addition to autocompletion it can:

• organize imports with smart selection regular classes;
• generate code (toString, hashCode, equals, constructors, accessors) with field selection;
• add abstract methods to implementing class;
• execute vimspector debug session;
• automatic installation of jdt.ls and java-debug extension;
• class creation methods from jc2.

Installation

Minimal setup using vim-plug:

call plug#begin('~/.vim/plugged')

Plug 'neovim/nvim-lspconfig'
Plug 'hrsh7th/nvim-cmp' 
Plug 'hrsh7th/cmp-nvim-lsp'
Plug 'williamboman/nvim-lsp-installer'
Plug 'puremourning/vimspector'
Plug 'mfussenegger/nvim-jdtls'
Plug 'artur-shaik/jc.nvim'

call plug#end()

lua require('jc').setup{}

Execute :PlugInstall and restart neovim.

For triggering autocompletion automatically consider configure nvim-cmp.

Configurations

g:jc_default_mappings – apply default mappings (default: 1)

g:jc_autoformat_on_save – execute code autoformatting on file save (default: 1)

Commands

• JCdebugAttach – start debug session with vimspector attaching to debug port;
• JCdebugLaunch – start debug session with vimspector executing main class;
• JCdebugWithConfig – start debug session using predefined vimspector's configuration;
• JCimportsOrganizeSmart – automatically organize imports using regular classes list;
• JCimportsOrganize – automatically organize imports choosing from available classes list;
• JCgenerateToString – choose fields and method to generate toString;
• JCgenerateHashCodeAndEquals – choose fields to generate hashCode and equals;
• JCgenerateAccessors – choose fields for accessors generation;
• JCgenerateAccessorGetter – generate getter for a field;
• JCgenerateAccessorSetter – generate setter for a field;
• JCgenerateAccessorSetterGetter – generate getter and setter for a field;
• JCgenerateConstructorDefault – generate constructor with no arguments;
• JCgenerateConstructor – choose fields for constructor;
• JCgenerateAbstractMethods – generate abstract methods;
• JCgenerateClass – start class generation user input prompt;
• JCtoggleAutoformat – enable/disable autoformat file on save;

Using nvim-jdtls:

• JCrefactorExtractVar – extract variable;
• JCrefactorExtractMethod – extract method;
• JCutilJshell – execute java shell;
• JCutilBytecode – extract bytecode for class;
• JCutilJol – analyze object layout scheme using jol.jar;
• JCutilUpdateConfig – update current project's configuration.

Default mappings

  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>ji", "<cmd>lua require('jc.jdtls').organize_imports(true)<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jI", "<cmd>lua require('jc.jdtls').organize_imports(false)<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "i", "<C-j>i", "<cmd>lua require('jc.jdtls').organize_imports()<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jts", "<cmd>lua require('jc.jdtls').generate_toString()<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jeq", "<cmd>lua require('jc.jdtls').generate_hashCodeAndEquals()<CR>", opts)

  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jA", "<cmd>lua require('jc.jdtls').generate_accessors()<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>js", "<cmd>lua require('jc.jdtls').generate_accessor('s')<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jg", "<cmd>lua require('jc.jdtls').generate_accessor('g')<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>ja", "<cmd>lua require('jc.jdtls').generate_accessor('gs')<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "i", "<C-j>s", "<cmd>lua require('jc.jdtls').generate_accessor('s')<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "i", "<C-j>g", "<cmd>lua require('jc.jdtls').generate_accessor('g')<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "i", "<C-j>a", "<cmd>lua require('jc.jdtls').generate_accessor('sg')<CR>", opts)

  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jc", "<cmd>lua require('jc.jdtls').generate_constructor(nil, nil, {default = false})<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jcc", "<cmd>lua require('jc.jdtls').generate_constructor(nil, nil, {default = true})<CR>", opts)

  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jam", "<cmd>lua require('jc.jdtls').generate_abstractMethods()<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "i", "<C-j>am", "<cmd>lua require('jc.jdtls').generate_abstractMethods()<CR>", opts)
  
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jda", "<cmd>lua require('jc.vimspector').debug_attach()<CR>", opts)

-- using `jdtls`
  vim.api.nvim_buf_set_keymap(bufnr, "v", "<leader>jre", "<Esc><Cmd>lua require('jdtls').extract_variable(true)<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>jre", "<Cmd>lua require('jdtls').extract_variable()<CR>", opts)
  vim.api.nvim_buf_set_keymap(bufnr, "v", "<leader>jrm", "<Esc><Cmd>lua require('jdtls').extract_method(true)<CR>", opts)

Class creation

Prompt scheme, for class creation:

template:[subdirectory]:/package.ClassName extends SuperClass implements Interface(String str, public Integer i):contructor:toString:equals

A: (optional) template - which will be used to create class boilerplate. Some existed templates: junit, interface, exception, servlet, etc;

B: (optional) subdirectory in which class will be put. For example: test, androidTest;

C: class name and package. With / will use backsearch for parent package to put in it. Without / put in relative package to current;

D: (optional) extends and implements classes will be automatically imported;

E: (optional) private str variable, and public i variable will be added to class;

F: (optional) contructor using all fields and toString will be created. Also hashCode and equals can be used.