Method Definitions Method Definitions InterSystems IRIS supports two types of methods: instance methods and class methods. An instance method is invoked from a specific instance of a class and performs some action related to that instance; this type of method is useful only in object classes. A class method is a method that can be invoked whether or not an instance of its class is in memory; this type of method is called a static method in other languages.See Method Syntax and Keywords in this reference. See also: Defining and Calling Methods Defining Method and Trigger Generators Adding Methods to a Class in Using Studio