Java date and time issue with BBB

When you use Java app, it uses standard library that probably doesn't use the RTC hardware. I would write my own and solve that problem. Read Date and time in Java about Unix time and you will understand why. The RTC chip on the other handle will be better if you read directly.

Clem

Ok, but my BBB is showing correct time on display on it's right corner just like our normal PC, but when we get time through java library it print's different one(time).

Trying not to be condescending, but what is displayed on BBB is not from Java library! Please read Date and time in Java to see what you will get in Java environment,,

Clem

Yes, i understand, it seems that BBB takes time from /etc/default/hwclock() ,I'm assuming because the RTC1 (DS1307) is loaded via a script when Debian boots the hwclock has already loaded and defaulted to RTC0 because my external RTC1 is yet to be loaded.

Note:

         i edit /etc/default/hwclock() to my external RTC1, but no result

this means that we need a way to set the time when the board is running. If you wish to set the time you could do it on a once-off basis…

root@beaglebone:~# date

Sat Jan  1 12:27:56 GMT 2000

Shell

root@beaglebone:~# ntpdate -b -s -u pool.ntp.org

root@beaglebone:~# date

Sat May 18 22:52:56 BST 2013

Next, find a NTP server that is close to your location. We need to do this to be good ‘ntp citizens’ as it is not good to use a NTP root server as they are already heavily loaded … it is better to use a NTP pool server that is close to your location in order to help with load balancing.

# This is the most basic ntp configuration file

# The driftfile must remain in a place specific to this

# machine - it records the machine specific clock error

driftfile /etc/ntp.drift

logfile /var/log/ntpd.log

# NTP Servers for Ireland from www.pool.ntp.org

server 0.ie.pool.ntp.org

server 1.ie.pool.ntp.org

server 2.ie.pool.ntp.org

server 3.ie.pool.ntp.org

# Using local hardware clock as fallback

# Disable this when using ntpd -q -g -x as ntpdate or it will sync to itself

# server 127.127.1.0

# fudge 127.127.1.0 stratum 14

# Defining a default security setting

restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

The LocalTime class is similar to the other classes whose names are prefixed with Local, but deals in time only. This class is useful for representing human-based time of day, such as movie times, or the opening and closing times of the local library. It could also be used to create a digital clock, as shown in the following example:

LocalTime thisSec;

for (;;) {

    thisSec = LocalTime.now();

    // implementation of display code is left to the reader

    display(thisSec.getHour(), thisSec.getMinute(), thisSec.getSecond());

}

The LocalTime class does not store time zone or daylight saving time information.

Had the same issue. Thankfully resolved.

Speaking of time zone, you can retrieve it as a symbol or offset from UTC along with the local date and time by using Java 8 class ZonedDateTime.  A simple example follows.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

import java.time.format.DateTimeFormatter; 
import java.time.ZonedDateTime;  
public class dateeg {
      public static void main( String [ ] args )      {
           ZonedDateTime zdt = ZonedDateTime.now();
           DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm:ss VV");
           System.out.println( "Now = " + zdt.format(formatter) );
      } 
}

Execution for me in Dallas Texas USA:
Now = 13:17:18 America/Chicago