To use the Java Web Start application on this page, you should have a recent Java installed, preferably 32-bit JRE (Java Runtime Environment) 1.8.0_20.

For most parts of North America, on Sunday at 2 AM in the morning on 2014-11-02 DST (Daylight Saving Time) ends. You should change all your clocks back one hour from 2:00 AM to 1:00 AM. Computer clocks will change themselves. If they don’t, you can use SetClock to prod them along. You will get an hour’s extra sleep. Don’t set the computer clock manually to adjust for DST end! Manually adjust your wrist watch, wall clocks, alarm clocks, microwave, stove, VCR (Videocassette Recorder)… Radio-Synched clocks should adjust themselves.

If you launch SetClock, now, (or later) it will set your PC (Personal Computer) clock to the accurate current time from an atomic clock on the web permitting Windows to automatically set your PC’s clock back one hour at the precise instant.


Click the orange launch button to run SetClock. Then click Get Time, then Set Time, then Exit.

SetClock is a Java Web Start program that sets your PC clock accurately by probing an atomic clock on the web. The atomic clock knows the precise UTC time, including leap seconds. If you are running Vista/W2008/W7-32/W7-64/W8-32/W8-64, then you must be running as an administrator or the SetClock program will be able to display the time, but will not be able to set it.

SetClock is also available with Java source to download. SetClock is not necessary for Vista/W2008/W7-32/W7-64/W8-32/W8-64, which has its own atomic clock setting procedure, though you can use SetClock if you want, or if you suspect your OS (Operating System) is not maintaining your clock’s accuracy.

You will get the most accurate results if you don’t have a lot of Internet activity running at the same time.

For SetClock to work, your PC clock must be configured to the correct time zone, and automatic daylight saving must be on. You can veryify they are set properly by left clicking the time in the bottom right corner of the screen ⇒ clicking change date and time settings ⇒ Clicking change time zone.

The clock inside your computer runs on UTC/GMT time, independent of your time zone or whether daylight saving is in effect. You must not manually adjust it for daylight saving changes. Your computer software will automatically change the displayed time to account for daylight saving so long as you have configured the correct time zone in the control panel. In any case, SetClock will undo the damage caused by someone fiddling with your computer’s clock.

Java Requirements and Troubleshooting

SetClock is a signed Java Web Start application to Set Clock. You are welcome to install it on your own website. If it does not work…
  1. Often problems can be fixed simply by clicking the reload button on your browser.
  2. In the Java Control Panel ⇒ security tab, configure medium security to allow self-signed and vanilla unsigned applets to run. If medium is not available, or if Java security is blocking you from running the program, configure high security and add to the Exception Site List at the bottom of the security tab.
  3. Make sure you have both JavaScript and Java enabled in your browser.
  4. Make sure the Java in your browser is enabled in the security tab of the Java Control panel. Click Start ⇒ Control Panel ⇒ Programs ⇒ Java ⇒ Security ⇒ Enable Java Content in the browser.
  5. This signed Java Web Start application needs 32-bit or 64-bit Java 1.7 or later. For best results use the latest 1.8.0_20.
  6. You also need a recent browser.
  7. It works under any operating system that supports Java e.g. W2K/XP/W2003/Vista/W2008/W7-32/W7-64/W8-32/W8-64/W2012/Linux/LinuxARM/LinuxX86/LinuxX64/Ubuntu/Solaris/SolarisSPARC/SolarisSPARC64/SolarisX86/SolarisX64/OSX
  8. You should see the Java Web Start above looking much like this screenshot. If you don’t, the following hints should help you get it working:
  9. For this Java Web Start to work, you must click grant/accept to give it permission to set your PC’s hardware clock. If you refuse to grant permission, the program may crash with an inscrutable stack dump on the console complaining about AccessController.checkPermission.
  10. Optionally, you may permanently install the Canadian Mind Products code-signing certificate so you don’t have to grant each time.
  11. If the above Java Web Start appears to freeze-up, click Alt-Esc repeatedly to check for any buried permission dialog box.
  12. If you have certificate troubles, check the installed certificates and remove or update any obsolete or suspected defective certificates. The only certificate used by this program is mindprodcert2014dsa.cer.
  13. Even if JWS (Java Web Start) complains that the certificate used to sign this application is “invalid”, please click grant/accept anyway.
  14. If the above Java Web Start does not work, or if it fails to automatically install the latest versions, try running:
    rem On Windows
    javaws.exe -viewer
    # on Linux/BASH
    javaws -viewer
    on the command line, then click show applications and delete any of the unworking or obsolete applications. Then click show resources and delete any of the unworking or obsolete resources. Then try launching the application again.
  15. If the above Java Web Start does not work, or if it fails to automatically install the latest versions, try uninstalling the JWS application in the control panel or uninstall it with:
    rem On Windows
    javaws.exe -viewer
    # on Linux/BASH
    javaws -viewer
    on the command line, and try launching the application again.
  16. If reinstalling does not work, especially if JWS appears to be using an obsolete *.jnlp file stuck in cache, try bulk uninstalling all JWS apps with:
    rem On Windows
    javaws.exe -uninstall
    # on Linux/BASH
    javaws -uninstall
    on the command line, and try launching the application again.
  17. If the error message says “program not found” the problem is likely a damaged association between *.jnlp files and the javaws.exe program. To learn how to repair the association, click the Repair button below.
  18. For Firefox, select open with: Java(TM) web start launcher.
  19. To ensure your Java is up to date, check with Wassup. First, download it and run it as an application independent of your browser, then run it online as an Applet to add the complication of your browser.
  20. If the above Java Web Start does not work, check the Java console for error messages.
  21. If the above Java Web Start does not work, you might have better luck with the downloadable version available below.
  22. This signed Java Web Start application requires modules from the Microsoft C++ Express 10 run time library. Normally they should be automatically statically included. However, if someone recompiled the JNI C++ code without the /MT option, this code will not work unless the vcredist_x86.exe Microsoft C++ Express 10 run time library is preinstalled. You can download it from Microsoft. The symptom of this problem is an UnsatisfiedLinkError or a side-by-side configuration error. Be sure to get the 2010 version. The older versions have the same name.
  23. If you are using Mac OS X and would like an improved Look and Feel, download the QuaQua look & feel from UnZip the contained quaqua.jar and install it in ~/Library/Java/Extensions or one of the other ext dirs.
  24. If you are using old versions of Microsoft Internet Explorer, try another browser.
  25. If you are using Microsoft Internet Explorer, you must click to allow blocked content permission for Active X to run. This also gives permission to Java to run. Click the Information bar, and then click Allow blocked content. Unfortunately, this also allows dangerous ActiveX code to run. However, you must do this in order to get access to perfectly-safe Java Applets running in a sandbox. This is part of Microsoft’s war on Java. Use a different browser.
  26. If you are using and older version Microsoft Internet Explorer, makes sure the Java Plug-In SSV helper add-in is installed and enabled. If it is not installed, try reinstalling the Java JRE.
  27. Try upgrading to a more recent version of your browser, or try a different browser e.g. Chrome, Firefox, SeaMonkey, Opera, Safari or Avant.
  28. If you still can’t get the program working click the red HELP button below for more detail.
  29. If you can’t get the above Java Web Start working after trying the advice above and from the red HELP button below, have bugs to report or ideas to improve the program or its documentation, please send me an email atemail Roedy Green.
Java powered   Get New Java   Get New Browser   Install or Repair JWS   Help

Unfortunately SetClock only works for Windows computers since it has to use a small piece of JNI (Java Native Interface) native code to actually set the system clock. If you are willing to port the tiny piece of JNI code to your platform, I would be happy to incorporate it so that SetClock works on your platform too.

Click the dark blue WebStart button at the top of the page to run the Setclock program.

8.6 2012-12-11 free Java
more infoprecisscreenshotbrowse source repository
for the current version of SetClock.
Set your PC Clock from an accurate atomic webserver clocks.
download 785K zip for SetClock Java source, compiled class files, jar and documentation to run on your own machine as a Java Web Start application.

Runs on any OS that supports Java e.g. W2K/XP/W2003/Vista/W2008/W7-32/W7-64/W8-32/W8-64/W2012/Linux/LinuxARM/LinuxX86/LinuxX64/Ubuntu/Solaris/SolarisSPARC/SolarisSPARC64/SolarisX86/SolarisX64/OSX.

First install the most recent Java.

To install, extract the zip download with WinZip, (or similar unzip utility) into any directory you please, often J:\ — ticking off the use folder names option.

To check out the corresponding source from the Subversion repository, use the TortoiseSVN repo-browser to
access setclock source in repository with [Tortoise] Subversion client on

To run the JWS application, modify the jnlp file to look in the right place for its files, then type:

javaws J:\com\mindprod\setclock\setclock.jnlp

adjusting as necessary to account for where the jar file is.

download ASP PAD XML program description for the current version of SetClock.

$1989.00 US donated so far. If the CMP utilities solved your problem, please donate a buck or two, or donate to one of the charities featured in the footer public service ads throughout the website and get a tax receipt.

SetClock is free. Full source included. You may even include the source code, modified or unmodified in free/commercial open source/proprietary programs that you write and distribute. Non-military use only.
atomic clock
Canadian Mind Products DSA code Signing Certificate
daylight saving time
Java Web Start
other downloads
radio-synched clock
time sources

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