What does “The field xxx is never used” mean? [closed]

Answer 1

The warning comes from static code analysis and is an indicator for code smell. Since you have not given us the code in question I will take a wild guess and assume that mids is the only private field, while the rest is internal or public.

Answer 2

This warning means exactly what it says. The field mids is never used anywhere else in the code. By used, it means nowhere is the field value set and nowhere is the field value accessed.

In essence, the field is dead code and the IDE/compiler is informing you the field is useless and can be removed without any harm to the remainder of the code.