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Bruno Borges
Bruno Borges

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Java devs: build something awesome with Copilot CLI and win big prizes

#githubcopilot #java #githubchallenge #devchallenge

Here’s today's invitation: join the GitHub Copilot CLI Challenge and build something with Copilot right in your terminal. Visit the Challenge page for rules, FAQ, and submission template.

Why I’m excited about Copilot CLI (especially for Java)

If you write Java for a living, you already know the truth: the terminal is where we build and test; it is where feedback loops are short; and where most productivity gains come from “small wins” repeated hundreds of times.

Most Java developers use Maven or Gradle, and IDEs (especially IntelliJ) have fantastic support for both. But in practice, we still drop to the terminal quite regularly:

  • run a very specific Maven goal or Gradle task
  • we want to reproduce CI as much as possible
  • add flags to isolate one failing test
  • check output in the same environment your teammates (and CI) will see
  • run a single test the same way CI does, but you don’t remember the exact incantation.

If we’re already inside the terminal running commands, we might as well ask Copilot CLI to help us do the right thing faster. GitHub Copilot CLI brings an agentic workflow to the place where those loops happen: the command line. And the best part: you can keep it grounded in your repo and your actual build output.

You can also join Johannes' live stream this week on the topic!

The challenge (quick overview)

The challenge is quite open-ended: build an application using GitHub Copilot CLI. But there is a judging criteria: (1) use of GitHub Copilot CLI; (2) share usability and user experience; and (3) must be original and creative!

The challenge is already up and running since January 22nd, but there is still time. The submissions are due by February 15th at 11:59 PM PST and the winners will be announced on February 26th.

This challenge comes with really cool prizes: the top 3 winners will get $1,000 USD plus a GitHub Universe 2026 ticket and a winner badge. Then, the next 25 runner-ups will get a 1-year GitHub Copilot Pro+ subscription with a runner-up badge. All valid submissions get a GitHub completion badge.

Ship a Java tool, for end-users or for developers

It can be a Spring Starter, a Quarkus Extension, a JavaFX application, a web application, Maven or Gradle plugins, a Java Swing application, plugins for IntelliJ or Eclipse, or even Apache JMeter! This is the kind of challenge where a small, well-executed tool can be more impressive than a giant “AI demo.” If you’re on the fence, here’s my recommendation:

  • pick a problem you hit every week
  • build a thin vertical slice in a day
  • make it pleasant to use
  • write a clean “how to run it” section
  • tell the story of how Copilot CLI helped you iterate

Need more to think on what to build?

These are Java-friendly ideas that fit the judging criteria and are designed to be realistic, shippable, and easy for judges to evaluate:

  • Test failure triage assistant for Maven/Gradle: parse surefire output, summarize likely causes, suggest next commands to run
  • Log explainer: ingest a stack trace + environment info and generate a focused explanation + remediation checklist
  • Repo onboarding CLI: generate a “first 30 minutes” guide for your project (build, tests, conventions, release process)
  • Changelog helper: read git history and propose a changelog entry + release notes draft
  • OpenAPI → Spring Boot starter: take an OpenAPI spec and scaffold a production-ready service layout

Prompts you can try today (copy/paste inspiration)

In your terminal (inside a repo), try asking Copilot CLI things like:

“Summarize why my Maven tests are failing from this output, then suggest the next 3 commands I should run.”
“Generate a JUnit 5 test for this class focusing on boundary cases.”
“Explain this stack trace like I’m onboarding to the project; point me to the likely source file and fix.”
“Propose a refactor that reduces duplication but keeps the public API stable.”
“Write a README section that explains how to run this tool, with examples.”

The key is to keep the agent grounded in real inputs: actual logs, actual code, actual constraints.

Programmatic control via the Copilot SDK for Java

If you want to build a Java app that programmatically drives Copilot CLI, start here:

https://github.com/copilot-community-sdk/copilot-sdk-java

More Resources

Use these to bootstrap your project fast:

Ready? Here’s your next step

If you build Java tools, this challenge is a great excuse to ship something useful and learn an agentic workflow you can reuse. Join the challenge and start your submission here:

https://dev.to/challenges/github-2026-01-21

If you do build something, tag me on DEV / socials — I’d love to see what you ship.

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