![]() In other words, a subclass can define the specific meaning of operations for its context i.e. A subclass may modify methods that maintain the structure of an interface with altered behavior. Superclass contains the following features that extend your Object-Oriented Design:Ī superclass represents a set of common properties inherited by its subclass. Because subclass extend the contents of a superclass, Java uses the keyword class extends. Superclass may be implemented as abstract class or base class types because they contain a group of common features that are extended in a subclass. In addition, methods and attributes may be specified with modifiers that regulate their accessibility. Variables that contain the values of an attribute within the class.Attributes that define the internal states of the class, and.Constructor which is a special method that initializes the state of an object upon its creation,.Methods contain the set of actions in the object definition,.The body of the class contains the implementation of associated methods and attributes within that class. A constructor is overloaded whenever we specify parameters. Default constructors are intended to initialize an object when there are no arguments passed into it. We say that a constructor is defined in default when it contains no parameters. Cannot be synchonized, abstract, static, and final.A constructor is a specialized method that must be defined with: Constructors can be parameterized or specified without parameters.Ī class may contain multiple constructors that configure an instantiated object accordingly. Java constructors initialize an instantiated object based on preconditions set by the caller. The class keyword signifies that we intend to begin creating a prototype of an object. ![]() Java uses a PascalCase naming convention for classes. In our code example, both ClassA and ClassC pertain to a class's namespace. The class name pertains to a namespace in which we can associate a coherent set of methods and data. This section contains the template for writing valid expressions inside a class in Java. Furthermore, one can instantiate an object of a base class. Unlike an abstract class, base classes cannot contain abstract methods, so extending base classes will inherit the properties associated with the base class. ![]() Base class - represents a parent class that other classes may extend.Additionally, one cannot create an instance of an abstract class because it is meant to create a prototype of a class – not an object instance. An abstract class may contain default implementation and abstract methods, which we will discuss in this section (Superclass or Supertypes). Abstract class - represents a set of rules that a concrete class must satisfy.But once specified as final a concrete class can no longer be extended. Like a base class, one can extend a concrete class. Concrete class - represents a concrete form of an object that may or may not be extended.In terms of design, there are three types of classes in Java:
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