As your doing a project of UCSD's "Object Oriented Programming in Java" Course, In the HelloWorld class comment out this code

AbstractMapProvider provider = new Google.GoogleTerrainProvider();

and this code in Offline part

provider = new MBTilesMapProvider(mbTilesString);

and remove the Provider in this code

map1 = new UnfoldingMap(this, 50, 50, 350, 500);

This does not use the google as a provider, and uses UnfoldingMap to display the map. Be sure that your using Java 8 and have a main method in the class

public static void main(String[] args) {
        PApplet.main("module1.HelloWorld");
}

Refer to this link: https://github.com/tillnagel/unfolding/issues/145#issuecomment-596135265