nvim-jls

Neovim integration for JLS (Java Language Server).

Why this plugin

JLS can run as a raw LSP server, but configuring it correctly is the hard part. This plugin removes the boilerplate:

• OS‑aware launcher resolution (dist/lang_server_{linux|mac|windows})
• Stable root detection for Maven/Gradle projects

Requirements

• Neovim 0.10+ – required for pull diagnostics (errors/warnings will not appear on older versions)
• JLS installed locally (build or release), with a dist/ folder
• Optional: nvim-lspconfig (plugin works without it)

JLS is not currently listed in nvim-lspconfig or mason because it does not meet their minimum GitHub star threshold yet. This plugin still works with or without nvim-lspconfig/mason; if they become available, you can use them alongside this plugin without changing your setup.

Quick start

-- lazy.nvim
{
  "idelice/nvim-jls",
  opts = {
    jls_dir = "/path/to/jls", -- must contain dist/lang_server_*.sh
    settings = {},
  },
}

JLS starts automatically on FileType=java via a filetype plugin. setup() is only needed if you want to override defaults.

Commands

• :JlsStart – start JLS for the current buffer
• :JlsRestart – restart JLS
• :JlsStop – stop all JLS clients
• :JlsLog – open Neovim's LSP log in a read-only buffer
• :JlsClearCache – delete this workspace's JLS disk cache
• :checkhealth jls – run the built-in health check

Configuration

require("jls").setup({
  jls_dir = nil,                 -- used to resolve dist/lang_server_*.sh
  settings = {},                 -- passed through to the JLS LSP settings payload
  root_markers = {
    "pom.xml",
    "build.gradle",
    "build.gradle.kts",
    "settings.gradle",
    "settings.gradle.kts",
    "WORKSPACE",
    "WORKSPACE.bazel",
    ".java-version",
    ".git",
  },
  inlay_hints = {
    enabled = false,             -- show parameter name hints at call sites
  },
})

nvim-jls does not choose the server JVM. It launches the packaged JLS launcher and passes through any LSP settings you configure. The current JLS distribution is built for Java 25 and runs on its packaged Java 25 runtime.

settings.java.configuration.runtimes may still be sent to JLS as part of the LSP configuration payload, but nvim-jls does not use that list to decide how the server process is started.

Inlay hints

Enable parameter name hints at call sites:

require("jls").setup({
  inlay_hints = { enabled = true },
})

Hints appear only for files in your workspace. JDK and dependency sources opened via go-to-definition are not annotated.