Inheritance

Inheritance is a way to define a class by reusing the definition of another class.

Related concepts:  ClassMemberSubtyping

Closest Wikipedia entry:  Inheritance (object-oriented programming) — In object-oriented programming, inheritance is the mechanism of basing an object or class upon another object (prototype-based inheritance) or class (class-based inheritance), retaining similar implementation. Also defined as deriving new classes (sub classes) from existing ones such as super class or base class and then forming them into a hierarchy of classes. In most class-based object-oriented languages like C++, an object created through inheritance, a "child object", acquires all the properties and behaviors of the "parent object", with the exception of: constructors, destructors, overloaded operators and friend functions of the base class.

Misconceptions about Inheritance

16 documented Misconceptions

AbstractClassMustImplementAbstractMethod

An abstract class must implement all abstract methods defined in its superclass

AbstractClassNoImplementation

An abstract class cannot contain implemented methods

ConcreteClassMustOverride

A concrete class needs to implement all methods declared in its abstract superclasses

ConcreteClassOnlyImplementClassAbstract

A concrete class only needs to implement those abstract methods it inherits from abstract superclasses

ConcreteClassOnlyImplementDirectAbstract

A concrete class only needs to implement abstract methods declared in its direct supertypes

ConcreteClassOnlyImplementInterfaceAbstract

A concrete class only needs to implement those abstract methods it inherits from interfaces

ImplicitInterfaceImplementation

Java implicitly produces implementations of any methods a class inherits from the interfaces it implements

InterfaceExtendClass

An interface can extend a class

NoMethodInheritance

Subclasses inherit fields but not methods

PrivateAccessibleInSubclass

Private members of a superclass are accessible from a subclass

StaticDispatch

The method to be called is determined by the static type

SubtypeCompatibleWithSupertype

A variable of a subtype can reference an object of a supertype

SuperAlwaysHasParentheses

To call a method on a superclass, parentheses are needed after the keyword super

SuperNotFirstStatement

super() can be called anywhere in the constructor of a subclass

SuperclassObjectAllocated

When instantiating an object of a subclass, an object of a superclass is also allocated

SupertypeIncompatibleWithSubtype

A variable of a supertype cannot reference an object of a subtype