1package coffee;
2
3class ElectricHeater implements Heater {
4  boolean heating;
5
6  @Override public void on() {
7    System.out.println("~ ~ ~ heating ~ ~ ~");
8    this.heating = true;
9  }
10
11  @Override public void off() {
12    this.heating = false;
13  }
14
15  @Override public boolean isHot() {
16    return heating;
17  }
18}
19