diff options
Diffstat (limited to 'content/guide')
| -rw-r--r-- | content/guide/neovim-as-a-java-ide.md | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/content/guide/neovim-as-a-java-ide.md b/content/guide/neovim-as-a-java-ide.md new file mode 100644 index 0000000..412a79d --- /dev/null +++ b/content/guide/neovim-as-a-java-ide.md @@ -0,0 +1,156 @@ +--- +title: Neovim as a Java IDE +date: 2026-02-21 +icon: neovim.png +--- + +## Préambule + +Most of the time, you can configure Neovim painlessly with a simple `vim.lsp.enable("some_lsp_server")`. And boom, autocompletion, go to definition. Everything works out of the box. But that's not the case with Java, you can't check the definition of classes from the `java`, `javafx` or whatever package that is outside of your project, and most of the time the language server takes forever to load up or simply doesn't start. + +To fix these issues, we will not enable `jdtls` from the `vim.lsp.enable` function, and we will use the `mfussenegger/nvim-jdtls` plugin. + +In this tutorial, I assume that you know how to download plugins and edit you `init.lua` file. You should also already have a completion plugin. + +## Versions + +I think that the version of `python`, `jdtls` and `nvim` might affect the accuracy of this tutorial. So I will give you the versions I use as a reference in case you encounter some bugs. + +```sh +% nvim --version +NVIM v0.11.6 +Build type: RelWithDebInfo +LuaJIT 2.1.1767980792 +``` + +```sh +# jdtls +jdt-language-server-1.55.0-202601131729.tar.gz +``` + +```sh +% python3 --version +Python 3.14.3 +``` + +```sh +% java --version +openjdk 25.0.2 2026-01-20 +``` + +## Downloading Java and jdtls + +### Java + +First of all, you should install OpenJDK. You should download the latest version (at the time being it's version 25, but 21 should work). + +### jdtls with pacman + +If you use `pacman` on your Linux distro it's really easy. Just build the AUR package : + +```sh +git clone https://aur.archlinux.org/jdtls.git +cd jdtls/ +makepkg -si +``` + +### jdtls without pacman + +On other distros, I do not know how to install jdtls with the 'official' way. I know you could download it with the [mason.nvim](https://github.com/mason-org/mason.nvim) plugin, but it will make you go through additional configuration steps. I prefer downloading `jdtls` and adding it to my `$PATH` myself. + +So first of all download the latest tarball. + +```sh +baseurl="https://download.eclipse.org/jdtls/milestones" + +ver=$( + curl -s "$baseurl/" | + grep -oE '/jdtls/milestones/[0-9]+\.[0-9]+\.[0-9]+' | + awk -F/ '{print $4}' | + sort -V | + tail -n1 +) + +file=$( + curl -s "$baseurl/$ver/" | + grep -oE "jdt-language-server-${ver}-[0-9]+\.tar\.gz" | + head -n1 +) + +curl -fL "https://www.eclipse.org/downloads/download.php?file=/jdtls/milestones/1.56.0/$file" -o jdtls.tar.gz +``` + +You should now have a `jdtls.tar.gz` file in your current working directory. Do not untar it now. + +Next create those folders : + +```sh +sudo mkdir -pv /usr/local/share/java/jdtls +``` + +And you can now extract the content of `jdtls.tar.gz` into `/usr/local/share/java/jdtls`. + +```sh +sudo tar xf jdtls.tar.gz -C /usr/local/share/java/jdtls +``` + +Next create a symlink to the `jdtls` binary in your $PATH : + +```sh +sudo ln -s --relative /usr/local/share/java/jdtls/bin/jdtls /usr/local/bin/jdtls +``` + +You have successfully installed jdtls ! + +## Configuring Neovim + +First of all, install the [mfussenegger/nvim-jdtls](https://github.com/mfussenegger/nvim-jdtls) plugin with your neovim plugin manager. + +Then, DO NOT enable `jdtls` with the `vim.lsp.enable` function. + +Instead, append this at the end of your `init.lua` file. + +```lua +vim.api.nvim_create_autocmd("FileType", { + pattern = "java", + callback = function(args) + local project_name = vim.fn.fnamemodify(vim.fn.getcwd(), ":p:h:t") + local workspace_dir = vim.fn.stdpath("data") .. + package.config:sub(1, 1) .. "jdtls-workspace" .. package.config:sub(1, 1) .. project_name + + local config = { + name = "jdtls", + cmd = { + "jdtls", + "-data", + workspace_dir, + }, + + root_dir = vim.fs.root(0, { ".git", "gradlew", "mvnw" }), + + -- 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 = { + } + }, + + + -- This sets the `initializationOptions` sent to the language server + -- If you plan on using additional eclipse.jdt.ls plugins like java-debug + -- you'll need to set the `bundles` + -- + -- See https://codeberg.org/mfussenegger/nvim-jdtls#java-debug-installation + -- + -- If you don't plan on any eclipse.jdt.ls plugins you can remove this + init_options = { + bundles = {} + }, + } + require('jdtls').start_or_attach(config) + end +}) +``` + +Now, if you restart Neovim, and open a Java file in a project that has a `.git`, `mvnw`, or `gradlew` file at the top level directory. jdtls should work out of the box and you will be able to use all it's lsp features. |