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Version: 1.3

Java

Install Syntax Highlighting​

:TSInstall java

Supported language servers​

  • jdtls

Supported formatters​

  • astyle
  • clang_format
  • google_java_format
  • npm_groovy_lint
  • uncrustify

The Java language server (jdtls) also supports formatting, and it is enabled by default. It is possible to fine-tune its formatting rules, but it is also possible to use a different formatter from the above list. When such a formatter is used, jdtls formatting will be disabled to avoid conflict.

jdtls​

jdtls is installed automatically once you open a .java file.

note

jdtls requires jdk-17 or newer to run.

Neovim (by default) passes basic options (such as vim.opt.shiftwidth and vim.opt.tabstop) to the language server when formatting.

It is possible to further customize jdtls formatting by supplying an Eclipse formatter file.

To do so, type :LspSettings jdtls. It will create a JSON file at .config/lvim/lsp-settings/jdtls.json and can be treated as global settings.

Add the following content:

{
  "java.format.settings.profile": "GoogleStyle",
  "java.format.settings.url": "https://raw.githubusercontent.com/google/styleguide/gh-pages/eclipse-java-google-style.xml"
}

To reference a local file in the url attribute, simply set its path: "java.format.settings.url": ".config/lvim/custom-formatter.xml"

It is also possible to specify project-specific configs. To do so, type :LspSettings local jdtls which will create .nlsp-settings/jdtls.json in the current working directory, and paste the config that we used for the global settings.

More information about Lsp commands can be found at https://github.com/tamago324/nlsp-settings.nvim

Custom formatters​

Custom formatters are CLI tools that are wrapped with null-ls plugin, which is available by default in LunarVim. They should be installed separately from LunarVim and be available on $PATH.

clang-format​

clang-format is traditionally used for formatting C/C++ code but can also be used for Java code formatting.

Prerequisites: clang-format should be on the $PATH

Enable formatter in ~/.config/lvim/config.lua:

local formatters = require "lvim.lsp.null-ls.formatters"
formatters.setup {
  {
    command = "clang-format",
    filetypes = { "java" },
  }
}

With the above configuration, the default settings will be used. To see the defaults, type clang-format --dump-config in the terminal.

clang-format supports multiple predefined styles. For the list of values see: https://clang.llvm.org/docs/ClangFormatStyleOptions.html#configurable-format-style-options

To specify such style you need to set extra args in config.lua:

  {
    command = "clang-format",
    filetypes = { "java" },
    extra_args = { "--style", "Google" },
  }

It is also possible to use a format file. For that, you will need a valid clang-format file. You can create one from an existing style that can be used as a base: clang-format --style=Google --dump-config > .clang-format

config.lua:

  {
    command = "clang-format",
    filetypes = { "java" },
    extra_args = { "--style", "file:<format_file_path>" },
  }

google-java-format​

google-java-format is a program that reformats Java source code to comply with Google Java Style.

Prerequisites: google-java-format should be on the $PATH

Enable formatter in ~/.config/lvim/config.lua:

formatters = require "lvim.lsp.null-ls.formatters"
formatters.setup {
  {
    command = "google-java-format",
    filetypes = { "java" },
  }
}

uncrustify​

uncrustify works similarly to clang-format.

Enable formatter in ~/.config/lvim/config.lua:

formatters = require "lvim.lsp.null-ls.formatters"
formatters.setup {
  {
    command = "uncrustify",
    filetypes = { "java" },
    extra_args = { "-c", "path/to/your.cfg" },
  }
}

Supported linters​

{ "checkstyle", "pmd", "semgrep" }

Advanced configuration​

It is also possible to fully customize the language server. See https://github.com/LunarVim/starter.lvim to get ideas on how to proceed with that.