This document discusses classes and objects in Java. It explains that in Java, all programs are based on classes which define the state and behavior of objects. Classes create objects and objects use methods to communicate. A class is a collection of fields (data) and methods (procedures or functions) that operate on that data. A class declaration specifies the class name, extends any superclasses, and contains field and method declarations. Methods are declared inside the class body after data fields. Objects are created dynamically using the new keyword and the class name.

1. CLASSES AND
OBJECT
A.Sangeetha M.Sc(info Tech)
Department Of Cs&it
Nadar Saraswathi College Of Arts And Science

2. INTRODECTION:
 Java is a true OO language and therefore the underlying
structure of all Java programs is classes.
 „Anything we wish to represent in Java must be encapsulated in
a class that defines the “state "and “behaviour”of
the basic program components known as objects.
 „C lasses create objects and objects use methods to
communicate between them.

3. CLASS:
A class is a collection of fields (data) and
method (procedure or function) that
operate on that data
child
Centre
radius
Circumference()
Radius()

4. A classes is a collection of
fields(data)and methods (procedure
or function)that operate on that
data.
class Cl a s s N a m e
[extends
Su p e r Cl a s s N a m e ]
{
[fields declaration]
[methods declaration]
}

5. Bare bone class-no fields,no method.
A class with only data fields has no life.
Objects created by such a class cannot
respond to any messages.
public class Circle {
// my circle class
}

6. Methods are declared inside the body of the
class but immediately after the declaration of
data fields.
„The general form of a method declaration is:
type Method
Name(parameter-list)
{
Method-body;

7.  Objects are created dynamically using the