How to set up nvim-jdtls for Java debugging with nvim-dap?

Install java-debug and vscode-java-test bundles, add them to the init_options in your Lua configuration, and ensure nvim-dap is available. Use functions like require('jdtls').test_class() for debugging tests, as outlined in the Debugger section.

nvim-jdtls vs IntelliJ IDEA for Neovim users?

nvim-jdtls offers a lightweight, configurable Neovim-native experience ideal for keyboard-centric workflows, while IntelliJ provides richer out-of-the-box tools and easier setup. Choose based on preference for customization over convenience.

Why is nvim-jdtls slow with code completions?

Completion requests are expensive on large projects; the README recommends tuning auto-completion plugins to be less aggressive or disabling them to avoid overloading the Eclipse JDT Language Server.

Can nvim-jdtls work with a Java project without Maven or Gradle?

Limited to syntax error reporting for single files; full features require a Maven or Gradle project. You can manually specify dependencies in configuration, but this is not recommended and less efficient.

How to fix nvim-jdtls not recognizing new dependencies?

Run :JdtUpdateConfig to refresh the configuration, or restart the language server. If issues persist, check log files with :JdtShowLogs for errors related to project setup.

What system requirements does nvim-jdtls have?

Requires Neovim >=0.6.0, Java 21 for eclipse.jdt.ls, Python 3.9 if using the jdtls script wrapper, and Maven or Gradle for project support. Ensure these are correctly installed and configured.

How to configure nvim-jdtls for multiple Java runtime versions?

Define runtimes in the settings, specifying paths for different JDKs (e.g., JavaSE-11, JavaSE-17) and use :JdtSetRuntime to switch at runtime, as detailed in the Troubleshooting section for language features.

Open-Awesome

nvim-jdtls

GPL-3.0Lua0.2.0

Extensions for the built-in LSP support in Neovim to integrate the Eclipse JDT Language Server for Java development.

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1.5k stars80 forks0 contributors

What is nvim-jdtls?

nvim-jdtls is a Neovim plugin that integrates the Eclipse JDT Language Server to provide advanced Java development features directly within the editor. It extends Neovim's built-in LSP support with refactoring tools, debugging capabilities, test generation, and other Java-specific functionalities, enabling a powerful, keyboard-driven development workflow.

Target Audience

Experienced Java developers who use Neovim as their primary editor and prefer a configuration-as-code approach over GUI-heavy IDEs. It assumes familiarity with Java build tools like Maven or Gradle.

Value Proposition

It offers a lightweight, highly configurable alternative to full IDEs, leveraging Neovim's native LSP client and extensibility. Developers choose it for its simplicity, scriptability, and deep integration with the Eclipse JDT Language Server without leaving the Neovim ecosystem.

Overview

MIRROR of: https://codeberg.org/mfussenegger/nvim-jdtls

Use Cases

Best For

Java developers who want a keyboard-centric, terminal-based workflow in Neovim
Setting up a lightweight Java IDE alternative with advanced refactoring tools
Integrating Java debugging and JUnit testing directly into Neovim via nvim-dap
Working on Maven or Gradle projects with full language server support
Extracting variables, methods, and constants with precise editor commands
Generating boilerplate code like constructors, toString, and equals/hashCode methods

Not Ideal For

Developers prioritizing quick, GUI-driven setup over configuration-as-code
Projects not using Maven or Gradle build systems (single-file or custom builds)
Teams needing out-of-the-box debugging and testing without manual bundle installation
Environments with Java versions below 21 or without Python 3.9 for the jdtls script

Pros & Cons

Pros

Advanced Refactoring Tools

Provides extract variable/method/constant, organize imports, and generate boilerplate code like constructors and toString, as detailed in the Extensions list, enabling precise code manipulation.

Integrated Debugging and Testing

Supports debugging applications and JUnit tests via nvim-dap with java-debug and vscode-java-test bundles, offering IDE-like capabilities directly in Neovim, per the Debugger section.

Extended Java-Specific Features

Includes bytecode viewing with javap, memory analysis with jol, and project-aware JShell, leveraging the Eclipse JDT Language Server for deep Java tooling beyond basic LSP.

Configuration-as-Code Flexibility

Follows the KISS principle, allowing experienced users to fully customize their setup through Lua scripts, as emphasized in the Philosophy and Configuration sections.

Cons

Complex Initial Setup

Requires separate installation of eclipse.jdt.ls, manual bundle configuration for debugging, and data directory management, with multiple troubleshooting steps needed for common failures.

Performance Overhead on Large Projects

Admits that completion requests can be slow on big projects and aggressive auto-completion plugins may overload the server, impacting responsiveness, as noted in the Troubleshooting section.

Dependency on External Tools

Needs Java 21, Python 3.9 for the jdtls script, and Maven/Gradle for full functionality, creating compatibility barriers and additional maintenance overhead.

Manual Bundle Management

Advanced features like debugging and test generation require downloading and configuring java-debug and vscode-java-test bundles separately, adding complexity compared to integrated IDEs.

Open Source Alternative To

nvim-jdtls is an open-source alternative to the following products:

IntelliJ IDEA

IntelliJ IDEA is a powerful integrated development environment (IDE) for Java and other JVM languages, developed by JetBrains, known for its intelligent code assistance and productivity features.

Visual Studio Code

A free, open-source code editor developed by Microsoft that supports debugging, embedded Git control, syntax highlighting, and extensions for many programming languages.

Eclipse

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