Class
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A class provides the specification and definition of properties, constructors, and methods for creating object instances of that class.
A class is the blueprint from which individual objects are created.
A class is created in java by writing code for a class definition. A class definition includes:
Class name
Class properties or instance variables
Class constructor methods
Class methods
It's important to distinguish between a class and an object. An object is created dynamically at run-time; it is considered an object-instance of a class that has been defined in code. To create an object instance, you will use the following syntax:
ObjectType variableName = new ObjectConstructor();
Ball ball1 = new Ball( ); Ball ball2 = new Ball( 10, 10 );
A UML Class diagram provides a diagramatic representation of the features of a class. In addition, a UML class diagram shows relationships between different classes, such as inheritance and composition.
The UML Class diagram below shows
class name: Ball,
class properties or instance variables: x, y, size.
methods (functions): move(), display( )
Some UML class diagrams also show constructor methods.
