title: How to create a trial version of a Java program
body: <p>I'm coding a software on java and i almost finished, i would like to know how can we create a trial version which work for example for 30 days, because i will to send it to some companies</p>
  
  <p>so how to make it like shareware or trialware, also can we block access to the .class in the jar file?</p>
  
  <p>Thank you </p>