music.java

几个简单的java学习代码

class Instrument {
  public void play(int n) {
    System.out.println("Instrument.play()");
  }
}

// Wind objects are instruments
// because they have the same interface:
class Wind extends Instrument {
  // Redefine interface method:
  public void play(int n) {
    System.out.println("Wind.play()");
  }
}

public class Music {
  public static void tune(Instrument i) {
    // ...
    i.play(1);
  }
  public static void main(String[] args) {
    Wind flute = new Wind();
    tune(flute); // Upcasting
  }
} ///:~