Class not found

help
1

Error: class not found: ?
Error: class not found: Main.java
spoj: The program compiled successfully, but main class was not found.
Main class should contain method: public static void main (String[] args).

How to solve this error even though I have named the file as Main.java and there is a class which is public and its name is Main and there is also a method public static void main(String args[]). I have attached the file instead of solving on the ide of codechef. Is this because of using multiple classes in a single file?

2

name class name as Codechef if submitting on codechef

3

No still its not getting executed .Do the class have to be public? Does codechef show whether there is a file attached or not? I cant see any label whether the file is attached.