Java NTP client

java ntp
Matt Howells picture Matt Howells · May 29, 2009 · Viewed 30.3k times · Source

I need my software to communicate with an NTP server to determine the local clock offset. I have tried using the org.apache.commons.net.ntp package, but its implementation is rather poor when running on Windows, because of the use of System.currentTimeMillis() to determine the time before and after the NTP packet exchange. As you may or may not know, this value is only updated when the system clock ticks, which on most modern Win2k3 servers is at 64Hz or every 15.625ms. This greatly limits the accuracy of the clock offset calculation.

Ntpd uses the CPU high-frequency timer to interpolate between system clock ticks, and achieve much higher resolution time. Do you know of a Java implementation that uses this or a similar technique? Or do you know of any other NTP implementation other than Apache's?

Answer

dfa picture dfa · May 29, 2009

there is a NTP Java implementation on support.ntp.org

Related questions

How to prevent usage of expired license through system clock tampering?

I am currently working on a license manager using java, I will be specifying a start and end date for my application so I can force a licensed user to re-license the program after a certain amount of time. But …

Read More
Getting time from public time server using TimeTCPClient

I try to use the following code to obtain time from public time server. package aaa; import java.util.Arrays; import java.util.List; import org.apache.commons.net.TimeTCPClient; public final class Main { public static java.util.Date getNTPDate() { …

Read More
How can I access NTP clock in java

I have a distributed program written in java. I want my nodes access a synchronized physical clock. I know NTP is a protocol for physical clock synchronization. I know that I can install it on linux by sudo apt-get ntp. …

Read More