What is the difference between 'Overriding' and 'Hiding/Method Shadowing'?
Overriding vs Method Hiding
Overriding replaces or specializes a virtual method implementation and participates in runtime polymorphism. Method hiding, or shadowing, defines a separate member with the same or related name in the derived class; the member selected can depend on the compile-time type of the reference. This distinction is important because hiding can produce surprising behavior when an object is accessed through a base-type reference. As a senior engineer, I prefer explicit overriding for polymorphic behavior and use hiding only when the semantics are intentional.
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Overriding is runtime polymorphism.
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The actual object's implementation is selected for an overridden virtual method.
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Hiding creates a distinct member in the derived class.
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With hiding, the compile-time/reference type can affect which method is selected.
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Hiding can make APIs confusing, so it should be explicit and intentional.
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The exact mechanics differ between Java and C#.
Follow-up Questions
- What is runtime polymorphism?
- How does method hiding work in C#?
- Does Java support method hiding?
- What happens when an overridden method is called through a base reference?
- When would intentional method hiding be appropriate?