关于DoubleClass类的问题。。。。。。请问DoubleClass是基本类吗？

[langson]

import java.io.*;

public class Example7_8
{
static BufferedReader keyboard=new BufferedReader(new InputStreamReader(System.in));

public static void main(String[] args) throws IOException
{

DoubleClass courseSocore = new DoubleClass();

System.out.println("Line 1: Baseed on course score, this program compute thecoure grade");

getScore(courseScore);

printGrade(courseScore.getNum());
}

public static void getScore(DoubleClass score) throws IOException
{

double s;
System.out.print("Line 5: Enter sourse score:");
System.out.flush();

s=Double.parseDouble(keyboard.readLine());
score.setNum(s);
System.out.println("\nLine 7: course Score is" + s);

}
public static void printGrade(double testScore)
{
System.out.print("Line 10: Your grade the courese is");

if(testScore >= 90)

System.out.println("A");
else if(testScore >= 80)
System.out.println("B");
else if(testScore >= 70)
System.out.println("C");
else if(testScore >=60)
System.out.println("D");
else
System.out.println("F");
}
}

　　请问,编译错误提法：找不到DoubleClass类，未定义。　DoubleClass courseSocore = new DoubleClass();　＝＝》　DoubleClass类要不要，自定义。应该怎么定义。本人是初学者。

[Paripatetic]

DoubleClass是什么？
是双精度浮点型么？
应该是Double吧

[紫炎圣骑]

我晕，哪有DoubleClass类，是Double