how to create a trial software code in java [duplicate]

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How to create a trial version of a Java program

I have created a java application. I need to give that application as trial version for 15 days.

How to write code to make my software as trial version, which follows the con开发者_Go百科dition:

1. If user changes the date or not, it should work only for 15 days.

Please require some ideas to implement in java for Windows currently.

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you can save the date on first activation in a file inside you package (call the file something which is not textual, you might also encrypt the data). when you see that user changed the date, because it do not match you first activation date or 15 passed disable the file. It would be even better if you install the file (should be dummy) with you package and then use it, if the user deleted it or changed it (you can add md5 signature) then you program will fail.