Editing COBOL (section)

====Object-oriented programming====
[[class (computer programming)|Classes]] and [[Interface (object-oriented programming)|interfaces]] have been in COBOL since 2002. Classes have factory objects, containing class [[method (computer programming)|methods]] and variables, and instance objects, containing instance methods and variables.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|loc=§ D.18.2}} Inheritance and interfaces provide [[polymorphism (computer science)|polymorphism]]. Support for [[generic programming]] is provided through parameterized classes, which can be instantiated to use any class or interface. Objects are stored as references which may be restricted to a certain type. There are two ways of calling a method: the {{code|INVOKE}} statement, which acts similarly to {{code|CALL}}, or through inline method invocation, which is analogous to using functions.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|loc=§ D.18}}

<syntaxhighlight lang="cobolfree">
*> These are equivalent.
INVOKE my-class "foo" RETURNING var
MOVE my-class::"foo" TO var *> Inline method invocation
</syntaxhighlight>

COBOL does not provide a way to [[Member visibility|hide]] methods. Class data can be hidden, however, by declaring it without a [[property (programming)|{{code|PROPERTY}}]] clause, which leaves external code no way to access it.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|p=108}} [[Method overloading]] was added in COBOL 2014.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|p=896}}