import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
 
public class Main {
    
    public static void main(String[] args) {
        
        List<Integer> ints = Arrays.asList(1, 2, 3);
        
        List<String> strings = new ArrayList(ints); //allowed, causes heap pollution
        
        String string = strings.get(0); //ClassCastException
    }
}