Java projects tend to have deep directory structures due to the package hierarchy used and the idioms of the build tools. So for example the directory that the code for the first module of this project is in:

src/main/java/uk/co/monotonic/testing/junit5/before/m2

Now really annoyingly the next.tech platform doesn't appear to let you resize the filetree horizontally or scroll horizontally. And as a result you can't actually browse to the directory with the Java code in and click to open it.

You can use the commandline to edit the file in vim, but that's not really very good when next.tech is supposed to be an editor in a browser. I've attached a screenshot to show the issue - you can see the filetree on the left:

Essentially this means that you can't actually see or edit files within the next.tech platform if you're using idiomatic Java directory structures.