superclasss

Superclass, in object-oriented programming, denotes a class from which other classes derive. A superclass provides fields (data members) and methods that are inherited by its subclasses, forming an inheritance hierarchy that supports code reuse, interface consistency, and polymorphism. A subclass can extend or specialize the behavior of its superclass, override methods, and add new members. In many languages, a subclass can also invoke the superclass implementation through a special keyword or mechanism (for example, super calls). Constructors in a subclass may initialize inherited state by invoking the superclass constructor.

Inheritance models vary by language. In languages with single inheritance (such as Java and C#), each class has at most one direct superclass, though they may implement multiple interfaces. In languages with multiple inheritance (such as C++ or Python), a class may have several direct superclasses, which can complicate method resolution and diamond problem handling. Some languages avoid these issues with mixins or interfaces that do not provide implementation.

In type systems used by functional languages, a related concept is a superclass constraint in type classes. For example, a type class may require another class as a prerequisite, indicating that any type that wants to be an instance of the first class must also be an instance of the second.

Semantic relationships are often described as parent, base, or ancestor in documentation and diagrams. The universal root class, such as Object in Java, serves as the ultimate superclass of all other classes in its hierarchy.

Note: the term 'superclasss' is a common misspelling; the standard plural is 'superclasses'.