我是Java编程的新手，无法弄清楚此编译错误“错误：不是语句”。

这只是一个测试程序，所以变量名不是那么好

import java.util.Random;

public class HelloWorld {

    String randomVariable;

    public void Room (String variable){

        randomVariable = variable;

    }

    public void howMany(){

        String answerToHowMany = "There are " + randomVariable + " walls in this room.";
        System.out.println(answerToHowMany);

    }

    public static void main(String[] args) {

        int randomWalls = (rand.nextInt(20) + 1); 

        Room newRoom = new Room(randomWalls);

        newRoom.howMany;

    }

}