CommandImplementations.java

public class TurnTVOn implements Command {

    Device device;

    public TurnTVOn(Device device) {
        this.device = device;
    }

    @Override
    public void execute() {
        device.on();
    }
}


public class TurnTVOff implements Command {

    Device device;

    public TurnTVOff(Device device) {
        this.device = device;
    }

    @Override
    public void execute() {
        device.off();
    }
}