//: generics/GenericsAndCovariance.java // ©2015 MindView LLC: see Copyright.txt import java.util.*; public class GenericsAndCovariance { public static void main(String[] args) { // Wildcards allow covariance: List flist = new ArrayList<>(); // Compile Error: can't add any type of object: // flist.add(new Apple()); // flist.add(new Fruit()); // flist.add(new Object()); flist.add(null); // Legal but uninteresting // We know that it returns at least Fruit: Fruit f = flist.get(0); } } ///:~