wind.java

java的容器应用

//: Wind.java
// Inheritance & upcasting
import java.util.*;

class Instrument {
	protected void play() { System.out.println("Instrument playing"); }
	static void tune(Instrument i) {
		i.play();
	}
}

// Wind object are instruments
// because then have the same interface:
class Wind extends Instrument {
	protected void play() { System.out.println("Wind playing"); }
	public static void main(String[] args) {
		Wind flute = new Wind();
		Instrument.tune(flute);
	}
}