Settings (formerly global properties 1.8 and below) are configuration variables that the user can set through the Administration menu, without restarting or recompiling the application. They're useful when module code needs to refer to a value that's unique to a particular installation, such as a concept ID number or a file path.
ADDING A SETTING (formerly global property 1.8 and below) FOR YOUR MODULE
Settings (formerly global properties 1.8 and below) are defined in your module's config file. The property is added when the module is started if it doesn't already exist in the OpenMRS installation. See the module config file documentation for instructions to define properties in your module.
READING A SETTING (formerly global property 1.8 and below) IN CODE
...