What is the * 'class' in swing user interface?

Question

I have seen this in my lecture's code examples but never in the main lecture notes. I haven't been able to find any information on it online either. What is the * 'class' (if it is even a class) in:

package graphicsExample;
import java.swing.*;
    ...

In other what's, what does importing this do?

Answer 1

It's importing all classes from a single package, ie

import javax.swing.*;

imports the classes/interfaces/enums/exceptions the classes listed here (not including nested classes/interfaces/ect.): https://docs.oracle.com/javase/8/docs/api/javax/swing/package-summary.html