The kettle.properties file is a file created by Spoon the first time you run the tool. The purpose of the file is to contain variable definitions with a broad scope: Java Virtual Machine.
Why should we define a variable in this file? If we want to use a variable in several jobs and/or transformations, and the values don't change from one Job/Transformation to another, then defining the variable in the kettle.properties file is a good idea. Now you may guess why we put the SMTP related variables in this file. It's highly probable that you reuse them in many other jobs. Also, there are low chances that the values change. In the kettle.properties file, you may define as many variables as you want. The ...
