找不到带引用变量的符号

Question

游戏和GameHelper分为两类，编译器显示两个错误

game.java:7：错误：找不到符号                 GameHelper helper = new GameHelper（）;
                ^       符号：类GameHelper   地点：上课游戏
game.java:7：错误：找不到符号
                GameHelper helper = new GameHelper（）;
                                      ^   符号：类GameHelper   地点：上课游戏
  2个错误

游戏类

class game
{
public static void main(String[]args)
{
    String g;
    sinkdot one=new sinkdot();
    GameHelper helper=new GameHelper();
    int randnum=(int)(Math.random()*7);
    int[] locs={randnum,randnum+1,randnum+2};
    int guesscount=0;
    one.locationsetter(locs);
    boolean isAlive=true;
    while(isAlive==true)
    {
        System.out.println("Enter your guess");
        g=helper.getUserInput("Enter a number");
        guesscount=guesscount+1;
        String returnval=one.checkyourself(g);
        System.out.println(returnval);
        if(returnval.equals("Kill"))
        {
            isAlive=false;
            break;
        }
    }
    System.out.println("Number of attempts are"+guesscount);
}
}

GameHelper类

import java.io.*;
public class GameHelper{
public String getUserInput(String prompt){
    String inputLine=null;
    System.out.print(prompt+" ");
    try{
        BufferedReader is=new BufferedReader(new InputStreamReader(System.in));
        inputLine=is.readLine();
        if(inputLine.length()==0){
        return null;
        }
        catch(IOException e){
            System.out.println("IOException:"+e);
        }
        return inputLine;
    }
}
}

我正在用javac game.java编译它。在sinkdot类中没有错误所以我没有提到它。