/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

import java.time.* ;
import java.time.temporal.* ;
import java.time.format.* ;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		
ZonedDateTime start = LocalDateTime
        .parse( "2017-10-28T15:00:00" )
        .atZone( ZoneId.of( "Europe/Berlin" ) ) ;  // Producing a `ZonedDateTime` instance. 

ZonedDateTime stop = LocalDateTime
        .parse( "2017-10-29T03:00:00" )
        .atZone( ZoneId.of( "Europe/Berlin" ) ) ; // Producing another `ZonedDateTime` instance. 

long hours = ChronoUnit.HOURS.between(  start ,  stop ) ;

System.out.println( "start.toString(): " +  start ) ;
System.out.println( "stop.toString(): " +  stop ) ;
System.out.println( "hours: " +  hours ) ;

	}
}