how can I do to know how many times the recipient open the email or the number of click? : <p>I'm working on an application in Java EE, one of the features of this application is to send emails using  javamail. 
I must make reporting on items , how can I do to know how many times the recipient open the email or the number of click?</p>

<p>Thank you in advance for your suggestions</p>
