// reuse/Wind.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// Inheritance & upcasting

class Instrument {

public void play() {}

static void tune(Instrument i) {

// ...

i.play();

}

}

// Wind objects are instruments

// because they have the same interface:

public class Wind extends Instrument {

public static void main(String[] args) {

Wind flute = new Wind();

Instrument.tune(flute); // Upcasting

}

}