Simple Date format returns Wrong date intermittently [duplicate]

Answer 1

SimpleDateFormat is not thread safe that's why you should check if in your calling code there is no issue with that.

Answer 2

I'm sure that if you don't use that static instance of SimpleDateFormat you will have no problem:

public static String getCurrentDateTime() {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date d = new Date();
    String datetime = sdf.format(d);
    return datetime;
}

See these links:
Why is Java's SimpleDateFormat not thread-safe?
"Java DateFormat is not threadsafe" what does this leads to?