cannot evaluate because of java.lang.IllegalStateException: Cannot evaluate, please specify projectName in launch.json

[lucian0c]

I cannot evaluate an expression in VSCode debugging tomcat.

I have this error.
cannot evaluate because of java.lang.IllegalStateException: Cannot evaluate, please specify projectName in launch.json..

My launch.json

{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"type": "java",
"name": "Debug (Launch) - Current File",
"projectName": "My API",
"request": "launch",
"mainClass": "${file}"
}
]
}

Environment
Operating System: Windows 10
JDK version: 11
Visual Studio Code version: 1.46.1
Java extension version: v0.9.1
Java Debugger extension version: v0.26.0
Is there anything else that i should change in my launch.json?

[codebling]

Right-click on a Java file (one without a main() function) and choose "Run Java" and you'll get a prompt with a few options. This prompt will show the project name.

As you can see in this screenshot of this Ant project, sometimes the project name is unpredictable.

See also this answer on StackOverflow