I am currently sending emails through the Java CRM SDK 7, which is working just fine. However, I can not figure out how to replace the variables in the template with data I am generating dynamically before sending out the email.

For example, I am sending an invite email that generates a unique sign-up code. In the template I have a button that says "Join Now" with a variable assigned to it "${my-link}". 

How can I replace the variable ${my-link} with my url String generated right before sending the email?

The sample I'm using is documented here: https://github.com/zoho/zohocrm-java-sdk-7.0/blob/master/samples/sendmail/SendMail.java