How is the working directory set in Groovy script?

We have an implementation of a kernel based on this one that incorporates the Micronaut framework (https://github.com/stainlessai/micronaut-jupyter). When we switch kernels from Groovy, however, the working directory changes and I can't figure out why.

Using this kernel from any path in the jupyter context, e.g., $HOME/my/working/dir, the code:
```
println new File(".").absolutePath
```
returns
```
$HOME/my/working/dir
```

How does this path get passed to the Groovy script code for running the cell?