个位高手看下点给改啊
abstract class Door{
abstract void open();
abstract void close();
}
interface Alarm{
void alarm();
}
class Alarm Door extends Door implements Alarm{
void open(){};
void close(){};
void alarm(){};
}

public class Thedoor

{
public static void main(String[] args)
{
Door door = new Door();
System.out.println( "Door.open() ");
System.out.println( "Door.close() ");
System.out.println( "Door.alarm() ");

}
}

[解决办法]
改好如下:
abstract class Door{
abstract void open();
abstract void close();
}
interface Alarm{
void alarm();
}
class AlarmDoor extends Door implements Alarm{
void open(){};
void close(){};
public void alarm(){};
}

public class Thedoor

{
public static void main(String[] args)
{
AlarmDoor door = new AlarmDoor();
System.out.println( "door.open() ");
System.out.println( "door.close() ");
System.out.println( "door.alarm() ");

}
}