Hello @rototbob,
The code example works in Processing 3.5.4.
There is no java.io.Serial in that Java version to create a conflict.
Processing 4.3 uses a newer Java version that now has this:
And this adds the ambiguity.
This came up in a search:
https://www.reddit.com/r/processing/comments/17c1aqs/type_serial_is_ambiguous/?rdt=57779
This also impacted this code and you can see the fix here:
If you are doing serial communications to an Arduino the choice of which Serial to use is obvious.
Adding a comment to this:
//import java.io.*;
Will yield a helpful tip in the console that suggests what to replace the * with:
:)