заменить русские буквы на английские java [требует правки]

private final static Map<Character, String> REPLACERS = new TreeMap<>();
static {
    REPLACERS.put('А', "A");
    REPLACERS.put('Б', "B");
    REPLACERS.put('В', "V");
    REPLACERS.put('Г', "G");
    REPLACERS.put('Д', "D");
    REPLACERS.put('Е', "E");
    REPLACERS.put('Ё', "YO");
    REPLACERS.put('Ж', "J");
    REPLACERS.put('З', "Z");
    REPLACERS.put('И', "I");
    REPLACERS.put('Й', "Y");
    REPLACERS.put('К', "K");
    REPLACERS.put('Л', "L");
    REPLACERS.put('М', "M");
    REPLACERS.put('Н', "N");
    REPLACERS.put('О', "O");
    REPLACERS.put('П', "P");
    REPLACERS.put('Р', "R");
    REPLACERS.put('С', "S");
    REPLACERS.put('Т', "T");
    REPLACERS.put('У', "U");
    REPLACERS.put('Ф', "F");
    REPLACERS.put('Х', "H");
    REPLACERS.put('Ц', "C");
    REPLACERS.put('Ч', "CH");
    REPLACERS.put('Ш', "SH");
    REPLACERS.put('Щ', "SCH");
    REPLACERS.put('Ъ', "''");
    REPLACERS.put('Ы', "YI");
    REPLACERS.put('Ь', "'");
    REPLACERS.put('Э', "YE");
    REPLACERS.put('Ю', "YU");
    REPLACERS.put('Я', "YA");
    REPLACERS.put('а', "a");
    REPLACERS.put('б', "b");
    REPLACERS.put('в', "v");
    REPLACERS.put('г', "g");
    REPLACERS.put('д', "d");
    REPLACERS.put('е', "e");
    REPLACERS.put('ё', "yo");
    REPLACERS.put('ж', "j");
    REPLACERS.put('з', "z");
    REPLACERS.put('и', "i");
    REPLACERS.put('й', "y");
    REPLACERS.put('к', "k");
    REPLACERS.put('л', "l");
    REPLACERS.put('м', "m");
    REPLACERS.put('н', "n");
    REPLACERS.put('о', "o");
    REPLACERS.put('п', "p");
    REPLACERS.put('р', "r");
    REPLACERS.put('с', "s");
    REPLACERS.put('т', "t");
    REPLACERS.put('у', "u");
    REPLACERS.put('ф', "f");
    REPLACERS.put('х', "h");
    REPLACERS.put('ц', "c");
    REPLACERS.put('ч', "ch");
    REPLACERS.put('ш', "sh");
    REPLACERS.put('щ', "csh");
    REPLACERS.put('ъ', "''");
    REPLACERS.put('ы', "yi");
    REPLACERS.put('ь', "'");
    REPLACERS.put('э', "ye");
    REPLACERS.put('ю', "yu");
    REPLACERS.put('я', "ya");
}

@Override
public String start(String text) {
    StringBuilder sb = new StringBuilder();
    for (char ch : text.toCharArray()) {
        String replacement = REPLACERS.get(ch);
        sb.append(replacement == null ? ch : replacement);
    }
    return sb.toString();
}