Latest change to JDK 9 String code introduced a non-benign data race:

    public int hashCode() {
        if (hash == 0 && value.length > 0) {
            hash = isLatin1() ? StringLatin1.hashCode(value)
                              : StringUTF16.hashCode(value);
        }
        return hash;
    }

The 'hash' field should only be read once into a local variable. The second racy read (at return) can read 0 while the 1st (at if) can read non-zero.