Run/Debug with launch.json configuration using "mainClass" fails with "internal error"

[robert engels]

I am using vscode 1.83.1

I have a valid configuration, like:

        {
            "type": "jdk",
            "name": "Main",
            "request": "launch",
            "mainClass": "cff.package.main.Main",
            "args": "dev",
            "vmArgs": "-Dmy-services=etc/services/dev-services.properties -Dorg.jboss.logging.provider=jdk"
        },

but when I run it I get the attached:

I am only able to run things using Gradle tasks or the 'tooltip runner' as in:

[robert engels]

I was able to narrow down the cause.

This fails if the launch.json specifies a mainClass attribute. This makes it impossible to use run/debug when a project contains multiple top-level entry points.

The only option that works is to go to the main class and use the Intellisense to run the class.

[Viktor Szathmáry]

I'm also experiencing this problem. The workaround suggested above doesn't work for me either, since there's a custom build (see also #18).

[Achal Talati]

I looked into this issue. Actually you need to provide absolute path to the mainClass. Please try using absolute path.

Example configuration:

{
    "version": "0.2.0",
    "configurations": [
    {
        "type": "jdk",
        "request": "launch",
        "name": "Main",
        "mainClass": "/Users/atalati/vscode-extension/testingProjects/simpleMavenProject/src/main/java/org/yourcompany/yourproject/SimpleMavenProject.java",
        "args": "dev",
        "vmArgs": ""
    }
    ]
}

[Achal Talati]

Also, please can you update here if it worked or not?

[Mike Hogye]

@Achal1607 this worked for me -- thank you 🙏

Having a field called mainClass that expects a path to a source file is ... surprising. Renaming it to something like mainSourceFile might save users some frustration.

[Hristo I Stoyanov]

@Achal1607 Not sure this is a good solution - what if the launch.json file is checked in Git and shared between team members with different project directories? Not very portable.