Detect encoding issues and warn user

[RandomByte]

Is your feature request related to a problem? Please describe.

When using the wrong configuration for *.properties file source encoding, or when using an invalid character or one that is not available for the desired encoding, the user should be warned.

Describe the solution you'd like

When a character can't be found in the configured encoding's code page, a warning should be logged, indicating a potential encoding issue, either with the file or through incorrect configuration.

Describe alternatives you've considered

Additional context