overriding

Overriding is a feature of object-oriented programming that allows a subclass to provide a new implementation of a method that is defined in its superclass. When a method is overridden, instances of the subclass will use the subclass’s version, enabling polymorphic behavior and the reuse of common code from the base class while tailoring details for specific types.

Typically, an overriding method must have the same name and parameter list as the method in the superclass. The runtime type of the object determines which version is executed, via dynamic dispatch. Some languages require explicit indication of an override, such as an annotation or keyword, to improve correctness and readability.

Rules vary across languages. Static methods, private methods, or constructors are generally not overridden. Many languages require that an overridden method preserve or widen the access level. Some languages support covariant return types or special rules for abstract methods; attempting to override a final method is an error.

The purpose of overriding is to customize behavior while preserving interface and inheritance relationships. It supports polymorphism, enabling code that operates on a base type to work with any subclass without modification.

Example: a base class Vehicle with a method move(). A subclass Car overrides move() to implement a car-specific movement, while other subclasses may provide their own versions. A reference of type Vehicle pointing to a Car object will invoke Car’s move method at runtime.

Overriding is distinct from overloading, which involves methods with the same name but different parameters. It is related to virtual methods, abstract methods, and interface implementation, and it can introduce design considerations such as the Liskov Substitution Principle.