How can I install a java file on this app

Question

I want to learn how to save data in a data bass and more but I dont know how to install the java files wish are needed

Answer 1

you can only paste code to editor (playground) and save it as one file to the archive.
Or you can create a file on server programmatically and use it as datafile, while this code reached the end of executing

Answer 2

Thanks zemiak