Java複習 9.1問題？？？

public class LampTest {public LampTest(){System.out.println("構造Lamp...");}public void ligth(){System.out.println("發光...");}public static void main(String[] args) {/*System.out.println("建立白熾燈...");IncandecentLamp iLamp=new IncandecentLamp();System.out.println("建立熒光燈...");LuorescentLamp ll=new LuorescentLamp();System.out.println("建立節能燈...");EnergySavingLamp el=new EnergySavingLamp();*/}}class Filament{public Filament(){System.out.println("開始構造燈絲..");}}class EnergySavingLamp extends LuorescentLamp{public EnergySavingLamp(){System.out.println("開始建立節能燈...");}}class IncandecentLamp extends LampTest{private Filament filament=new Filament();public IncandecentLamp(){System.out.println("開始建立白熾燈...");}public Filament getFilament() {return filament;}public void setFilament(Filament filament) {this.filament = filament;}}class LuorescentLamp extends LampTest{public LuorescentLamp(){System.out.println("開始建立熒光燈...");}private static Filament filament=new Filament();public static Filament getFilament() {return filament;}public static void setFilament(Filament filament) {LuorescentLamp.filament = filament;}}

輸出為：

開始構造燈絲..

不是什麼都沒有嗎？ 為什麼還有輸出？？？？？？？？？