The class is still there, implicitly.

The main function can be written with `String[] args` if you need it.

This is a decent summary of the changes:

https://www.happycoders.eu/java/main-method/

Further details:

https://openjdk.org/jeps/512

,,Since an implicitly declared class cannot be accessed from outside, it must always contain a main method.’’

This looks like a hack just for the main file, it would have been good if these functions can be called from other files.

And now to know what it does you have to read a book.

The IO class is good. The rest is information hiding. Now if you could write anything else in Java in this form,it would make sense.