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C++ does not have the keyword super that a subclass can use in Java to invoke the superclass version of a method that it wants to override. Instead, the name of the parent or base class is used followed by the scope resolution operator. For example, the following code presents two classes, the base class Rectangle, and the derived class Box.
According to Java Language Specification: [5] A type variable is an unqualified identifier. Type variables are introduced by generic class declarations, generic interface declarations, generic method declarations, and by generic constructor declarations. A class is generic if it declares one or more type variables. [6]
In object-oriented programming, a covariant return type of a method is one that can be replaced by a "narrower" (derived) type when the method is overridden in a subclass. A notable language in which this is a fairly common paradigm is C++. C# supports return type covariance as of version 9.0. [1]
As a result, often the clone() method can only be used if the actual class of an object is known, which is contrary to the abstraction principle of using the most generic type possible. For example, if one has a List reference in Java, one cannot invoke clone() on that reference because List specifies no public clone() method.
One of the most important capabilities that a method provides is method overriding - the same name (e.g., area) can be used for multiple different kinds of classes. This allows the sending objects to invoke behaviors and to delegate the implementation of those behaviors to the receiving object.
An identifier is the name of an element in the code. There are certain standard naming conventions to follow when selecting names for elements. Identifiers in Java are case-sensitive. An identifier can contain: Any Unicode character that is a letter (including numeric letters like Roman numerals) or digit. Currency sign (such as ¥).
In Java, this will mean that the method in the derived class will implicitly override the method in the base class, even though that may not be the intent of the designers of either class. To mitigate this, C# requires that if a method is intended to override an inherited method, the override keyword must be specified. Otherwise, the method ...
The method with the most specific argument classes is chosen (D>(B,C)>A) ; then in the order in which parent classes are named in the subclass definition (B>C). However, the programmer can override this, by giving a specific method resolution order or stating a rule for combining methods.