Cannot find main method for Maven project with subprojects

[mrcjkb]

Environment

• Operating System: Arch Linux
• JDK version: liberica-jdk-11-full
• Visual Studio Code version: VSCodium 1.56.2
• Java extension version: 0.77.0
• Java Debugger extension version: 0.33.1

Steps To Reproduce

Given a Maven project with subprojects, such as this one
And VSCode is open with the cwd set to the root of the project
And I open a file in one of the subprojects (e.g. XChartDemo.java)
And the language server starts successfully
And I wait for long enough for the project to be loaded
When I try to run the main method

Current Result

Then I get an error message:

Error: Main method not found in the file, please define the main method as: public static void main(String[] args)

Source: Debugger for Java (Extension)

Expected Result

Then the main method is started

Log

lsp.log

[ryno1234]

Bump?

[siebonguyen]

I am having same trouble with running a single java file in a maven sub-project. Don't event think that this issue takes too long time to solved or I have to back to super-weight eclipse IDE.
Hope it will be solved soon.

Updated:
I found that the problem comes from jdk 11, which is the lowest version allowed by VS Code.
Since my project requires jdk 8.
I think there is no choice for me than bring the eclipse back.

[github-actions]

Hi Marc Jakobi (@mrcjkb), I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

Solution

• Ensure you open the root folder of your multi-module Maven project (containing the parent pom.xml) as a workspace folder in VS Code, not just a single .java file. VS Code needs the full project structure to detect submodules and their main methods.
• In the Java Projects or Maven explorer:
  • Click the Refresh button to re–import all modules.
  • Confirm that each subproject appears under Projects and that its src/main/java is marked as a source folder.
• Once the modules are loaded, you should see Run | Debug codelenses above your public static void main(String[] args).
• If it still doesn’t work:
  1. Run Java: Clean the Java language server workspace (F1 → type Java: Clean).
  2. Reload the window (F1 → Developer: Reload Window).
  3. Check the Java Language Server logs for errors (F1 → Java: Open All Log Files).

Other references with high confidence

• cannot find main method (cannot find main method #1207)
  • A generic troubleshooting thread where missing code lenses are often caused by workspace setup issues. Suggests opening a clean workspace and sharing logs if the problem persists. cannot find main method #1207 (comment)

The team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!

[mrcjkb]

I don't use vscode-java-debug anymore. Unsubscribing.

[siebonguyen]

I successfully using Java Debug on VS Code:

What I have done:

1. Install Extension Pack for Java
2. Install Community Server Connector and tomcat 8.5.50
3. set java home for Java Extension Pack and Community Server Connector in VS Code's settings.json:

"java.jdt.ls.java.home": "d:\\Apps\\jdk\\x64\\jdk-18.0.2",							// java home for java extension pack
"rsp-ui.rsp.java.home": "D:\\Apps\\jdk\\x64\\jdk-11.0.18"							// java home for Community Server Connector extension

4. Reload VS Code