the java-I/O-class itself is not included

import comp102x.IO;
public class test10x
{
public static void main (String[] args)
{
double eingabe, ausgabe;
IO.output("bitte double:");
eingabe = IO.inputDouble();
ausgabe = eingabe;
System.out.println(ausgabe);
System.out.println("this is the end of the program");
}
}