public static String toLowerCase(String in) {
        // def is picked from http://docs.oracle.com/javase/6/docs/api/java/lang/String.html#toLowerCase%28%29
        // Also, at the time of writing, English is the default language for queries
        if (in == null) return null;
        return Lowercase.toLowerCase(in);
    }
The lower casing method to use in Vespa when doing language independent processing of natural language data.
It is placed in a single place to ensure symmetry between e.g. query processing and indexing.

Return a lowercased version of the given string. Since this is language independent, this is more of a case
normalization operation than lowercasing.

@param in the string to lowercase
@return a string containing only lowercase characters
linguistics/src/main/java/com/yahoo/language/LinguisticsCase.java