> For the complete documentation index, see [llms.txt](https://kdoore.gitbook.io/cs1335/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kdoore.gitbook.io/cs1335/java/java_syntax/class.md).

# Class

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. [Java Specification (Oracle) ](https://docs.oracle.com/javase/tutorial/java/concepts/class.html)

## Class Definition

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

## Creating Objects

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 );

## UML Class Diagram

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.

![](https://2312795435-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M0-KLgCFUL-cVHjEcqM%2F-M0-KO91ISxRnRVYcAC8%2F-M0-KdQ4ywxM_jUGy7AB%2FScreenshot%202016-09-16%2008.30.08.png?generation=1581627413857839\&alt=media)