Tutorial on Development using Neovim

Lesson 1: Project Setup

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 1: Project Setup#

In this lesson, you’ll learn how to create and open a Java project in Neovim.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Create a simple Java project structure
Create Maven and Gradle projects
Open projects in Neovim
Navigate the file explorer

Creating a Simple Java Project#

Let’s start by creating a basic Java project structure manually:

# Create project directory
mkdir -p ~/java-projects/hello-neovim
cd ~/java-projects/hello-neovim

# Create standard Java directory structure
mkdir -p src/main/java/com/example
mkdir -p src/test/java/com/example

This creates the standard Maven/Gradle directory layout.

Lesson 2: Hello World

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 2: Hello World#

In this lesson, you’ll write your first Java program in Neovim and learn the basics of editing with Vim motions.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Write a simple Java program
Understand Vim modes (Normal, Insert, Visual)
Use basic editing commands
Save and run your program

Vim Modes Quick Reference#

Neovim has different modes for different tasks:

Mode	Purpose	How to Enter
Normal	Navigate and execute commands	Press `Esc`
Insert	Type and edit text	Press `i`, `a`, `o`, etc.
Visual	Select text	Press `v`, `V`, `Ctrl-v`
Command	Run commands	Press `:`

Tip: You’ll spend most time in Normal mode, briefly entering Insert mode to type.

Lesson 3: Code Completion

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 3: Code Completion#

In this lesson, you’ll learn to use IntelliSense-style auto-completion powered by the Java Language Server (jdtls).

Learning Objectives#

By the end of this lesson, you’ll be able to:

Use auto-completion while typing
Navigate completion suggestions
Accept and dismiss completions
Understand completion sources (LSP, snippets, buffer)

How Auto-Completion Works#

Neovim4j uses nvim-cmp for completion, which combines multiple sources:

LSP (jdtls) - Intelligent Java completions
Snippets - Common code patterns
Buffer - Words from open files
Path - File paths

Basic Completion Usage#

Auto-Trigger#

Start typing, and completions appear automatically:

Lesson 4: Creating Classes

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 4: Creating Classes#

In this lesson, you’ll learn different ways to create Java classes and use code actions to generate boilerplate code.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Create classes using the file explorer
Use fuzzy finder to create files quickly
Generate constructors, getters, and setters
Use code actions effectively

Method 1: File Explorer#

The traditional way using nvim-tree:

Open file explorer: <Space>ne
Navigate to src/main/java/com/example/
Press a (add file)
Type filename: Person.java
Press Enter

The file opens, ready for editing.

Lesson 5: Managing Packages

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 5: Managing Packages#

In this lesson, you’ll learn how to organize Java code using packages and navigate package structures efficiently.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Understand Java package structure
Create new packages
Move classes between packages
Navigate package hierarchies
Handle package declarations and imports

Understanding Java Packages#

Packages are Java’s way of organizing related classes. They:

Prevent naming conflicts
Control access with package-private visibility
Make code easier to find and maintain
Map to directory structure

Package Naming Conventions#

Standard format: com.company.project.module

Lesson 6: Buffer Navigation

Mon, 01 Jan 0001 00:00:00 +0000

In this lesson, you’ll learn to efficiently work with multiple files (buffers) open simultaneously in Neovim.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Understand buffers, windows, and tabs
Switch between open files quickly
Split windows horizontally and vertically
Navigate between splits
Manage buffer lifecycle

Understanding Buffers, Windows, and Tabs#

Buffers#

A buffer is an in-memory representation of a file. When you open a file, it loads into a buffer.

Lesson 7: Code Navigation

Mon, 01 Jan 0001 00:00:00 +0000

In this lesson, you’ll learn to navigate large Java codebases efficiently using LSP-powered features.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Jump to definitions and declarations
Find all references to a symbol
Navigate type hierarchies
Search for symbols across the project
Use the jump list effectively

Go to Definition#

Place cursor on a class, method, or variable and press:

Lesson 8: Debugging

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 8: Debugging#

In this lesson, you’ll learn to debug Java applications using Neovim’s DAP (Debug Adapter Protocol) integration.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Set and remove breakpoints
Start debug sessions
Step through code
Inspect variables
Evaluate expressions
Use the debug REPL

What is DAP?#

DAP (Debug Adapter Protocol) is like LSP but for debugging. Neovim4j uses:

nvim-dap - Debug adapter client
nvim-dap-ui - Beautiful debug UI
nvim-jdtls - Java debug adapter integration for jdtls

Debug UI Overview#

When you start debugging, the UI shows:

Lesson 9: Testing

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 9: Testing#

In this lesson, you’ll learn to write, run, and manage JUnit tests directly from Neovim.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Write JUnit tests
Run individual tests
Run test classes and test suites
Interpret test results
Debug failing tests
Use test-driven development workflow

JUnit Basics#

Test Structure#

A typical JUnit test class:

package com.example;

import org.junit.Test;
import static org.junit.Assert.*;

public class CalculatorTest {

 @Test
 public void testAdd() {
 Calculator calc = new Calculator();
 int result = calc.add(2, 3);
 assertEquals(5, result);
 }

 @Test
 public void testDivide() {
 Calculator calc = new Calculator();
 int result = calc.divide(10, 2);
 assertEquals(5, result);
 }

 @Test(expected = ArithmeticException.class)
 public void testDivideByZero() {
 Calculator calc = new Calculator();
 calc.divide(10, 0); // Should throw exception
 }
}

Common Assertions#

assertEquals(expected, actual);
assertTrue(condition);
assertFalse(condition);
assertNull(object);
assertNotNull(object);
assertSame(expected, actual); // Same reference
assertArrayEquals(expectedArray, actualArray);

Running Tests in Neovim#

Run Tests via Build Tool#

The most reliable way to run tests is using your build tool directly:

Lesson 10: Common Workflows

Mon, 01 Jan 0001 00:00:00 +0000

Lesson 10: Common Workflows#

In this final lesson, you’ll learn real-world workflows that combine everything you’ve learned into productive development patterns.

Learning Objectives#

By the end of this lesson, you’ll be able to:

Implement new features efficiently
Fix bugs systematically
Refactor code safely
Work with existing codebases
Optimize your development workflow

Workflow 1: Implementing a New Feature#

Scenario: Add User Authentication#

Let’s implement a complete authentication feature.

Step 1: Plan the Implementation#

Create a TODO list (use comments or :TodoWrite):

Tutorial on Development using Neovim

Lesson 1: Project Setup

Lesson 1: Project Setup#

Learning Objectives#

Creating a Simple Java Project#

Lesson 2: Hello World

Lesson 2: Hello World#

Learning Objectives#

Vim Modes Quick Reference#

Lesson 3: Code Completion

Lesson 3: Code Completion#

Learning Objectives#

How Auto-Completion Works#

Basic Completion Usage#

Auto-Trigger#

Lesson 4: Creating Classes

Lesson 4: Creating Classes#

Learning Objectives#

Method 1: File Explorer#

Lesson 5: Managing Packages

Lesson 5: Managing Packages#

Learning Objectives#

Understanding Java Packages#

Package Naming Conventions#

Lesson 6: Buffer Navigation

Lesson 6: Buffer Navigation#

Learning Objectives#

Understanding Buffers, Windows, and Tabs#

Buffers#

Lesson 7: Code Navigation

Lesson 7: Code Navigation#

Learning Objectives#

Core Navigation Commands#

Go to Definition#

Lesson 8: Debugging

Lesson 8: Debugging#

Learning Objectives#

What is DAP?#

Debug UI Overview#

Lesson 9: Testing

Lesson 9: Testing#

Learning Objectives#

JUnit Basics#

Test Structure#

Common Assertions#

Running Tests in Neovim#

Run Tests via Build Tool#

Lesson 10: Common Workflows

Lesson 10: Common Workflows#

Learning Objectives#

Workflow 1: Implementing a New Feature#

Scenario: Add User Authentication#

Step 1: Plan the Implementation#