Try Out Development Containers: Java

A development container is a running Docker container with a well-defined tool/runtime stack and its prerequisites. You can try out development containers with GitHub Codespaces or Visual Studio Code Remote - Containers.

This is a sample project that lets you try out either option in a few easy steps. We have a variety of other vscode-remote-try-* sample projects, too.

Note: If you already have a Codespace or dev container, you can jump to the Things to try section.

Setting up the development container

GitHub Codespaces

Follow these steps to open this sample in a Codespace:

1. Click the Code drop-down menu and select the Open with Codespaces option.
2. Select + New codespace at the bottom on the pane.

For more info, check out the GitHub documentation.

VS Code Remote - Containers

If you already have VS Code and Docker installed, you can click the badge above or here to get started. Clicking these links will cause VS Code to automatically install the Remote - Containers extension if needed, clone the source code into a container volume, and spin up a dev container for use.

Follow these steps to open this sample in a container using the VS Code Remote - Containers extension:

1. If this is your first time using a development container, please ensure your system meets the pre-reqs (i.e. have Docker installed) in the getting started steps.

2. To use this repository, you can either open the repository in an isolated Docker volume:

   • Press F1 and select the Remote-Containers: Try a Sample... command.
   • Choose the "Java" sample, wait for the container to start, and try things out!

     Note: Under the hood, this will use the Remote-Containers: Clone Repository in Container Volume... command to clone the source code in a Docker volume instead of the local filesystem. Volumes are the preferred mechanism for persisting container data.

   Or open a locally cloned copy of the code:

   • Clone this repository to your local filesystem.
   • Press F1 and select the Remote-Containers: Open Folder in Container... command.
   • Select the cloned copy of this folder, wait for the container to start, and try things out!

Things to try

Once you have this sample opened, you'll be able to work with it like you would locally.

Note: This container runs as a non-root user with sudo access by default. Comment out "remoteUser": "vscode" in .devcontainer/devcontainer.json if you'd prefer to run as root.

Some things to try:

1. Edit:
   • Open src/main/java/com/mycompany/app/App.java.
   • Try adding some code and check out the language features.
   • Notice that the Java extension pack is already installed in the container since the .devcontainer/devcontainer.json lists "vscjava.vscode-java-pack" as an extension to install automatically when the container is created.
2. Terminal: Press Ctrl+Shift+` and type uname and other Linux commands from the terminal window.
3. Build, Run, and Debug:
   • Open src/main/java/com/mycompany/app/App.java.
   • Add a breakpoint.
   • Press F5 to launch the app in the container.
   • Once the breakpoint is hit, try hovering over variables, examining locals, and more.
4. Run a Test:
   • Open src/test/java/com/mycompany/app/AppTest.java.
   • Put a breakpoint in a test.
   • Click the Debug Test in the Code Lens above the function and watch it hit the breakpoint.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

License

Copyright © Microsoft Corporation All rights reserved.
Licensed under the MIT License. See LICENSE in the project root for license information.