[JDEV] Expiry date

[Matt Tucker]

Colin,

This is pretty off-topic for the jdev list. You should take the question 
to a Java community site such as:

  * forum.java.sun.com
  * www.javaranch.com
  * java.net

The only really secure way to have a time-limited demo is to have a 
license file with a specific end date (so, the license file they 
download to use changes every day to be 30 days in the future or 
whatever). The license file should be signed using your public key, then 
your software can verify the key to make sure the date is correct (your 
code should be obfuscated so that people can't decompile it to change 
the key verification step). There are number of software products you 
can purchase that do all this logic for you. They might even have some 
workarounds for not using a license file, such as trying to hide an 
expiration date in the Windows registry, etc.

Regards,
Matt

Colin Bell wrote:

> Hi all
> 
> I'm trying to create a time limited trial version of my java web app. 
> All I need to do is figure out a way to keep track of the date. ie store 
> the date and then check it, add a day until x number of days has passed. 
> I could just create text file, but that would be too easy to find and 
> delete. Does anyone have a technique or tip for doing this kind of thing 
> ? Is there perhaps an ability to store a bit of information in the JVM 
> indefinitely ?
> 
> Many thanks
> 
> Colin
> 
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