Java error: class found on application class path

I searched and found an email like TOEIC reading area fingerprint. To summarize:

When I first saw the warning "error: class found on application class path: A", I misread it as "not found" error. [Frequently: The warning itself means that there is a class, so it doesn't have the impression that it's an error warning] If there's no problem, can we rewrite it more clearly? "Warning: A compiled class named <Full Class Name> already exists in the application classpath. You cannot write the class as a source for running a single file source code program." Like this.

That's what they say. I don't know about Java, but I hope this is a hint.