class AlphanumericRandomStringService implements RandomStringService {

    @Override
    public String random() {
        return new RandomStringGenerator.Builder().withinRange('0', 'z').filteredBy(new CharacterPredicate() {
            @Override
            public boolean test(final int codePoint) {
                return Character.isAlphabetic(codePoint) || Character.isDigit(codePoint);
            }
        }).build().generate(8);
    }

}