标准接口

package class1;

interface USB {
public void start() ;
public void stop() ;

}

class Computer {
public static void plugin(USB usb){
usb.start() ;
System.out.println("====usb设备工作======");
usb.stop();
}

}

class Flash implements USB {
public void start() {
System.out.println("u盘开始工作。");
}
public void stop() {
System.out.println("u盘停止工作。");
}

}

class Print implements USB{
public void start() {
System.out.println("打印机开始工作。") ;
}
public void stop() {
System.out.print("打印机停止工作。");
}

}

public class InterfaceCaseDemo02 {
public static void main(String[] args) {
Computer.plugin(new Flash()) ;
Computer.plugin(new Print()) ;
}

}