The Savvy Java Developer's Guide to AI Coding Assistants - Windsurf | Cursor | Copilot

The AI coding assistant landscape is evolving at warp speed, and for Java developers, the choices are getting more powerful and specialized. Today, let's dive into how Windsurf , Cursor , and GitHub Microsoft Copilot compare and what makes each of them stand out.

Cursor: The AI-First IDE with Deep Codebase Understanding

An AI-powered code editor built on top of VS Code, designed to integrate AI capabilities more deeply into the development workflow.

Standout Features for Java:

Superior Codebase Understanding: This is where Cursor truly shines. It understands your entire project's structure, coding style, and even team best practices, providing highly relevant and tailored suggestions across multiple files.

Advanced Refactoring Tools: Excels at optimizing and improving existing Java code, making it ideal for code quality improvement and modernizing legacy code (e.g., converting anonymous classes to lambdas, applying design patterns).

Agent Mode: Its agent mode is more sophisticated, capable of analyzing tasks, breaking them down, and executing steps, even running terminal commands and incorporating documentation.

Contextual Awareness: Easily reference files, folders, code snippets, and even external documentation using @ symbols in your prompts, providing the AI with rich context.

Key takeaway

If deep codebase understanding, advanced refactoring, and a more "agentic" AI experience are high priorities for your Java projects, Cursor is a strong contender.

1 Prompt = 1 Running Spring Boot App

In this demonstrations, I have used common prompt across Windsurf, Cursor & Microsoft Copilot to effective compare the generated codes for code quality, usability of latest Java features and the efforts needed to get the application running.

Generate a simple Spring Boot REST API for managing a list of books.
The application should have:
1. An entity `Book` with fields: `id` (Long), `title` (String), `author` (String), `publicationYear` (Integer).
2. A Spring Data JPA repository for `Book`.
3. A REST controller for `Book` that supports the following endpoints:
    - GET /api/books: Get all books
    - GET /api/books/{id}: Get a book by ID
    - POST /api/books: Create a new book
    - PUT /api/books/{id}: Update an existing book
    - DELETE /api/books/{id}: Delete a book
4. Use an in-memory database (like H2) for simplicity.
5. Include basic exception handling for "Book Not Found" scenarios.
6. Provide necessary Spring Boot starter dependencies in `pom.xml`.        

Hands-on With Cursor

1. With Cursor, I have used default "Agent" mode which generates a full-fledge runnable application with single prompt.
2. I started with an empty directory in Cursor and pasted the entire prompt into its AI command palette. Cursor then initiated a multi-step generation process.
3. Cursor effectively created all folder structure and generated Entity, Controller, Repository classes - no manual touch points, automatically updated needed dependencies in POM
4. Cursor needed no code adjustments. The code generated is run-ready.

Windsurf: The Agentic Code Editor for Flow State Development

An AI-powered IDE (formerly Codeium) that goes beyond suggestions, aiming to be an "agentic" partner that understands your intent and actively assists across your workflow. It's built to keep you in a "flow state."

Standout Features for Java:

Cascade (The AI Agent): This is Windsurf's core. Cascade understands your project deeply, generates, runs, and even debugs code across files. It's designed to anticipate your needs and handle complex tasks autonomously.

Multi-file Editing & Code Generation: Can make coherent changes across multiple files, generating substantial, well-structured code.

"Supercomplete" & Intelligent Indexing: Beyond standard autocomplete, Supercomplete predicts your intent by analyzing code context before and after the cursor, while intelligent indexing creates a deep semantic understanding of your codebase.

Write Mode vs. Chat Mode: Offers both a "Write Mode" for direct code modification and a "Chat Mode" for interactive Q&A and explanations.

Terminal Integration & Auto-Execution: Can suggest and even auto-execute terminal commands, keeping you in the IDE.

Flexible AI Model Selection: Gives you access to a wide range of AI models, from Llama to Claude 3.5 Sonnet and GPT-4.

Key takeaway

Windsurf is ideal for those looking for an AI that acts more like a proactive development partner, capable of taking on larger, multi-file tasks and integrating deeply into the development flow. The flexible model selection enables developers to choose the model with right pricing and need.

Hands-on With Windsurf

1. With Windsurf, I have used GPT-4 model for demonstration with Cascade Agent Mode. This generates a full-fledge runnable application with single prompt. I have however observed better performance with Claude Sonnet 3.5 - it can effectively create Apache Flink run-ready application in minutes.
2. I started with an empty directory in Windsurf and pasted the entire prompt into Cascade AI. Cursor then initiated a multi-step generation process.
3. Cascade effectively created all folder structure and generated Entity, Controller, Repository classes - no manual touch points, automatically updated needed dependencies in POM
4. Cascade needed no code adjustments. The code generated is run-ready.

GitHub Copilot: The Ubiquitous Pair Programmer

The original AI pair programmer, deeply integrated with GitHub and broadly adopted across various IDEs (VS Code, JetBrains, Eclipse, etc.).

Standout Features for Java:

Excellent Code Completion & Suggestions: Provides context-aware suggestions for lines, methods, and even entire functions, significantly speeding up boilerplate code generation and common patterns (e.g., implementing sorting algorithms, API integrations, basic UI components with JavaFX, JDBC queries).

Wide Language Support: While we're talking Java, Copilot's strength lies in its ability to assist across a vast array of programming languages.

Basic Refactoring & Debugging Help: Can suggest simple refactoring and potential fixes for errors.

Documentation Generation: Helps in generating comments and documentation for your code.

Growing Agent Mode: New agent capabilities are emerging, allowing it to tackle more complex tasks and interact with your project more broadly.

Key takeaway

Your reliable workhorse for everyday coding tasks, especially if you're looking for strong inline suggestions and are already deeply embedded in the GitHub ecosystem.

Hands-on With Copilot

1. With Copilot, I used GPT-4, it generates code in chat window.
2. Folder structure is not generated, generated Entity, Controller, Repository classes are available are correct and valid. However, it needs to be rightly placed in project structure.
3. Code generated is not run-ready. POM needs to be updated for dependencies manually, parent POM was not added by default with the prompt in action.

The AI coding assistant landscape is undoubtedly flourishing, and for Java developers, the advancements offered by tools like Windsurf, Cursor, and GitHub Copilot are truly exciting. We've seen how each tool approaches code generation, codebase understanding, and workflow integration with its own unique strengths.

Cursor stands out with its deep codebase understanding and sophisticated Agent Mode, making it a powerful choice for complex refactoring and tasks requiring extensive context.

Its ability to deliver a full, runnable Spring Boot application from a single prompt, without manual adjustments, is a testament to its "AI-first" design.

Windsurf, with its "Agentic" approach and the powerful Cascade AI, is positioned as a proactive development partner.

Its multi-file editing capabilities, "Supercomplete" feature, and flexible AI model selection (including Claude 3.5 Sonnet, which showed impressive results for complex applications) indicate its potential for handling larger, more integrated tasks and keeping developers in a true "flow state."

Finally, GitHub Copilot remains the familiar and widely adopted "pair programmer."

While it might require more manual setup for full application generation compared to the other two, its excellent code completion, broad language support, and growing agent capabilities make it an indispensable tool for everyday coding tasks and those deeply integrated into the GitHub ecosystem.

Share your insights and experiences in the comments below! Let's collectively learn how these innovative tools are shaping the future of Java development.

#windsurf #copilot #cursor #genai #java #vibecoding