How to disable my java application after a few days

Question

I have a java application as a MyApplication.jar file. On clicking this .jar my application starts. I want to distribute this jar to my friends so that they can run the application and use it. However, I want my application to run only for a few days. The jar should become unusable after say 10 days and no one (including the people holding the jar) should be able to execute it.

Answer 1

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...I want to distribute this jar to my friends so that they can run the application and use it. However, I want my application to run only for a few days. >Just a wild guess. You don't have many friends*, do you?
In any case, the usual way to approach this task is to write a key to the system that contains the first date the software was run, then check it each subsequent launch. If the 'first date' + 'allowable days' is before 'today', pop a message telling the user that the software has expired.
As to how/where to store this information..
You might use the Properties class to read/write the date property.
Problems with this approach are
a) Users adjusting their system clock to a previous date to get software to work again.
b) Users finding and deleting the file containing the 'first date' property.
c) Users leaving the software running for 173 consecutive days.
d) * Users hating the software so much that they come and burn your house down.
( That last one is the real worry. ;)