When initially created, S1943 was reporting on any usage of FileWriter and FileReader. It made sense at the time since there was no way to create these classes with a defined charset.
SONARJAVA-3057, we made sure to report only the constructors without charset.
However, we still report FP due to this new API:
We should not report an issue in these cases (whatever the actual java version), and only report when a noncompliant constructor is found.