class LocalDate {
    public String toString() {
        if (absYear < 1000) {
            if (yearValue < 0) {
                buf.append(yearValue - 10000).deleteCharAt(1);
            } else {
                buf.append(yearValue + 10000).deleteCharAt(0);
            }
       // ...
    }
}
Currently, LocalDate.toString causes an extra memory copy when processing years < 1000. This can be replaced by using StringBuilder.repeat, which is more concise and has better performance.