☕ nvim-java

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Just install and start writing public static void main(String[] args).

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Tip

You can find cool tips & tricks here https://github.com/nvim-java/nvim-java/wiki/Tips-&-Tricks

📢 Demo

Demo.mp4

💫 Features

• ✅ Spring Boot Tools
• ✅ Diagnostics & Auto Completion
• ✅ Automatic Debug Configuration
• ✅ Organize Imports & Code Formatting
• ✅ Running Tests
• ✅ Run & Debug Profiles
• ✅ Built-in Application Runner with Log Viewer
• ✅ Profile Management UI
• ✅ Decompiler Support
• ✅ Code Actions

🔨 How to Install

🔸details

Requirements: Neovim 0.11+

Using vim.pack

vim.pack.add({
  {
    src = 'https://github.com/JavaHello/spring-boot.nvim',
    version = '218c0c26c14d99feca778e4d13f5ec3e8b1b60f0',
  },
  'https://github.com/MunifTanjim/nui.nvim',
  'https://github.com/mfussenegger/nvim-dap',

  'https://github.com/nvim-java/nvim-java',
})

require('java').setup()
vim.lsp.enable('jdtls')

Using lazy.nvim

Install using lazy.nvim:

{
  'nvim-java/nvim-java',
  config = function()
    require('java').setup()
    vim.lsp.enable('jdtls')
  end,
}

Yep! That's all :)

⌨️ Commands

🔸details

Build

• JavaBuildBuildWorkspace - Runs a full workspace build

• JavaBuildCleanWorkspace - Clear the workspace cache (for now you have to close and reopen to restart the language server after the deletion)

Runner

• JavaRunnerRunMain - Runs the application or selected main class (if there are multiple main classes)

:JavaRunnerRunMain
:JavaRunnerRunMain <arguments> <to> <pass>

• JavaRunnerStopMain - Stops the running application
• JavaRunnerToggleLogs - Toggle between show & hide runner log window

DAP

• JavaDapConfig - DAP is autoconfigured on start up, but in case you want to force configure it again, you can use this API

Test

• JavaTestRunCurrentClass - Run the test class in the active buffer
• JavaTestDebugCurrentClass - Debug the test class in the active buffer
• JavaTestRunCurrentMethod - Run the test method on the cursor
• JavaTestDebugCurrentMethod - Debug the test method on the cursor
• JavaTestViewLastReport - Open the last test report in a popup window

Profiles

• JavaProfile - Opens the profiles UI

Refactor

• JavaRefactorExtractVariable - Create a variable from value at cursor/selection
• JavaRefactorExtractVariableAllOccurrence - Create a variable for all occurrences from value at cursor/selection
• JavaRefactorExtractConstant - Create a constant from the value at cursor/selection
• JavaRefactorExtractMethod - Create a method from the value at cursor/selection
• JavaRefactorExtractField - Create a field from the value at cursor/selection

Settings

• JavaSettingsChangeRuntime - Change the JDK version to another

💻 APIs

🔸details

Build

• build.build_workspace - Runs a full workspace build

require('java').build.build_workspace()

• build.clean_workspace - Clear the workspace cache (for now you have to close and reopen to restart the language server after the deletion)

require('java').build.clean_workspace()

Runner

• built_in.run_app - Runs the application or selected main class (if there are multiple main classes)

require('java').runner.built_in.run_app({})
require('java').runner.built_in.run_app({'arguments', 'to', 'pass', 'to', 'main'})

• built_in.stop_app - Stops the running application

require('java').runner.built_in.stop_app()

• built_in.toggle_logs - Toggle between show & hide runner log window

require('java').runner.built_in.toggle_logs()

DAP

• config_dap - DAP is autoconfigured on start up, but in case you want to force configure it again, you can use this API

require('java').dap.config_dap()

Test

• run_current_class - Run the test class in the active buffer

require('java').test.run_current_class()

• debug_current_class - Debug the test class in the active buffer

require('java').test.debug_current_class()

• run_current_method - Run the test method on the cursor

require('java').test.run_current_method()

• debug_current_method - Debug the test method on the cursor

require('java').test.debug_current_method()

• view_report - Open the last test report in a popup window

require('java').test.view_last_report()

Profiles

require('java').profile.ui()

Refactor

• extract_variable - Create a variable from value at cursor/selection

require('java').refactor.extract_variable()

• extract_variable_all_occurrence - Create a variable for all occurrences from value at cursor/selection

require('java').refactor.extract_variable_all_occurrence()

• extract_constant - Create a constant from the value at cursor/selection

require('java').refactor.extract_constant()

• extract_method - Create method from the value at cursor/selection

require('java').refactor.extract_method()

• extract_field - Create a field from the value at cursor/selection

require('java').refactor.extract_field()

Settings

• change_runtime - Change the JDK version to another

require('java').settings.change_runtime()

🗜️ How to Use JDK X.X Version?

🔸details

Use vim.lsp.config() to override the default JDTLS settings:

vim.lsp.config('jdtls', {
  settings = {
    java = {
      configuration = {
        runtimes = {
          {
            name = "JavaSE-21",
            path = "/opt/jdk-21",
            default = true,
          }
        }
      }
    }
  }
})

🔧 Configuration

🔸details

For most users changing the default configuration is not necessary. But if you want, following options are available:

require('java').setup({
  -- Startup checks
  checks = {
    nvim_version = true,        -- Check Neovim version
    nvim_jdtls_conflict = true, -- Check for nvim-jdtls conflict
  },

  -- JDTLS configuration
  jdtls = {
    version = '1.43.0',
  },

  -- Extensions
  lombok = {
    enable = true,
    version = '1.18.40',
  },

  java_test = {
    enable = true,
    version = '0.40.1',
  },

  java_debug_adapter = {
    enable = true,
    version = '0.58.2',
  },

  spring_boot_tools = {
    enable = true,
    version = '1.55.1',
  },

  -- JDK installation
  jdk = {
    auto_install = true,
    version = '17',
  },

  -- Logging
  log = {
    use_console = true,
    use_file = true,
    level = 'info',
    log_file = vim.fn.stdpath('state') .. '/nvim-java.log',
    max_lines = 1000,
    show_location = false,
  },
})

⛳ Architecture

🔸details

Following is the high level idea. Jdtls is the language server nvim-java communicates with. However, we don't have all the features we need just in Jdtls. So, we are loading java-test & java-debug-adapter extensions when we launch Jdtls. Once the language server is started, we communicate with the language server to do stuff.

For instance, to run the current test,

• Request Jdtls for test classes
• Request Jdtls for class paths, module paths, java executable
• Request Jdtls to start a debug session and send the port of the session back
• Prepare TCP connections to listen to the test results
• Start nvim-dap and let user interactions to be handled by nvim-dap
• Parse the test results as they come in
• Once the execution is done, open a window show the test results

  ┌────────────┐                         ┌────────────┐
  │            │                         │            │
  │   Neovim   │                         │   VSCode   │
  │            │                         │            │
  └─────▲──────┘                         └──────▲─────┘
        │                                       │
        │                                       │
        │                                       │
        │                                       │
┌───────▼───────┐                ┌──────────────▼──────────────┐
│               │                │                             │
│   nvim-java   │                │   Extension Pack for Java   │
│               │                │                             │
└───────▲───────┘                └──────────────▲──────────────┘
        │                                       │
        │                                       │
        │                                       │
        │                                       │
        │                                       │
        │              ┌───────────┐            │
        │              │           │            │
        └──────────────►   JDTLS   ◄────────────┘
                       │           │
                       └───▲───▲───┘
                           │   │
                           │   │
                           │   │
                           │   │
                           │   │
  ┌───────────────┐        │   │         ┌────────────────────────┐
  │               │        │   │         │                        │
  │   java-test   ◄────────┘   └─────────►   java-debug-adapter   │
  │               │                      │                        │
  └───────────────┘                      └────────────────────────┘

📑 Projects Acknowledgement

• spring-boot.nvim is the one that starts sts4 & do other necessary jdtls sts4 sync command registration in nvim-java.

• nvim-jdtls is a plugin that follows "Keep it simple, stupid!" approach. If you love customizing things by yourself, then give nvim-jdtls a try.