What does "some characters cannot be mapped using cp1252" mean when saving?

Question

Java

Tell me another way to solve, otherwise I don’t fully understand, the essence of the error is the language input did not coincide with the default one, right?

Answer 1

It is obvious that you are trying to convert text into cp1252 that contains characters not provided for by this encoding (for example, Cyrillic, Greek letters, or some specific characters such as paragraph or pseudographic icons)
Save / output the text as utf-8 and see which of the presented characters is missing in the table