@Override
    public String toString() {
        String s = "Match of " + fCharsetName;
        if (getLanguage() != null) {
            s += " in " + getLanguage();
        }
        s += " with confidence " + fConfidence;
        return s;
    }
generates a hashCode based on the confidence value

@return the hashCode
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-text-module/src/main/java/org/apache/tika/parser/txt/CharsetMatch.java