ADDITIONAL SYSTEM INFORMATION :
Tested on Windows, Mac OS, Ubuntu Linux on Java versions 8, 9, 11.

A DESCRIPTION OF THE PROBLEM :
When using DateTimeFormatter.ISO_LOCAL_DATE_TIME and any other value, from Java 9 and onwards the format will always contain nanoseconds in the ending, like '2019-04-16T13:32:50.694395' in spite of documentation giving the explicit example '2011-12-03T10:15:30'. For java 8 however it will provide the exact same format as the documentation example. This should either be reflected in documentation from version 9 and onward, or change the behavior to be in line with the documentation.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the following code in java 9


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A date formatted like '2019-04-16T13:39:45'
ACTUAL -
A date formatted like '2019-04-16T13:39:45.272079'

---------- BEGIN SOURCE ----------
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;

public class Main {

    public static void main(String[] args) {
        ZonedDateTime dateTime = ZonedDateTime.now();
        DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
                .toFormatter();
        String answerTime = formatter.format(dateTime);
        System.out.println(answerTime);
    }
}

---------- END SOURCE ----------

FREQUENCY : always