Servant is used for providing some behavior to a group of classes. Instead of defining that behavior in each class - or when we cannot factor out this behavior in the common parent class - it is defined once in the Servant.

Use the Servant pattern when

• when we want some objects to perform a common action and don't want to define this action as a method in every class.

• Let's Modify the Objects-First Approach into Design-Patterns-First