java - 为什么会出现此错误？

这是代码：

class Acount
{ int sum ; String owner ; //these seem to make sense
    //a constructor or two
    public Acount ()
    { this.sum = 0 ; this.owner = "John Doe" ; }

    public Acount (String name)
    {this.sum = 0 ; this.owner = name ; }

    public Acount (String name, int sum)
    {this.sum = sum ; this.owner = name ; }

    //prints an acount in the format "owner" "sum"
    public static void printAcount (Acount Acount)
    {System.out.print (Acount.owner) ; System.out.print (" ") ; System.out.println (Acount.sum) ; }

    public static void main (String[]arg)
    {
        Acount Acount1 = new Acount ("david", 100) ;
        System.out.println ("heres the first acount as it was created:") ;
        printAcount (Acount1) ;
        System.out.println ("now i changed one of its instance varaibles with a static method") ;
        upOne (Acount1) ;
        printAcount (Acount1) ;
    }

    public static Acount upOne (Acount Acount)
    {
        Acount.sum = Acount.sum + 1 ;
        return Acount ;
    }
}

这是错误：

Exception in thread "main" java.lang.NoClassDefFoundError: Acount/java

出了什么问题，为什么？

最佳答案

您是如何在命令行中运行Java程序的？

java Account.java

如果是，请删除.java，因为java命令采用的是类名，而不是文件名。
正确的命令是：

java Account

另外，请确保您正确编译了文件。