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what exactly is object

By: aijaz_*** On: Wed Jan 29 18:09:34 IST 2014     Question Reputation0 Answer Reputation0 Quiz Belt Series Points0  0Blank User
consider an example
class sample(){

}

main()

sample s = new sample();

In the above example is "s" object or object reference variable??. In most of the sites n videos they say it as both, I'm confused help me out		Up0Down

 
Object


A runtime entity that has state and behaviour is known as an object. For example: chair, table, pen etc. It can be tengible or intengible (physical or logical).

An object has three characterstics:

state:represents the data of an object.
behaviour:represents the behaviour of an object.
identity:Object identity is typically implemented via a unique ID. The value of the ID is not visible to the external user, but is used internally by the JVM to identify each object uniquely.

For Example: Pen is an object. Its name is Reynolds, color is white etc. known as its state. It is used to write, so writing is its behaviour.
Object is an instance of a class.Class is a template or blueprint from which objects are created.So object is the instance(result) of a class. 		Image Created0Down
By: [email protected] On: Wed Jan 29 18:16:46 IST 2014 Question Reputation2 Answer Reputation0 Belt Series Points0 2User Image
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The above answer which u gav is generalised one,I need with an example. My doubt is related to practicality not theoritical.Image Created0Down
By: [email protected] On: Wed Jan 29 18:22:58 IST 2014 Question Reputation0 Answer Reputation0 Belt Series Points0 0User Image
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Objname = new <clsname ()
Clsname represents name of the
treated as object. New is called dynamic memory allocation operator
Clsname () represents constructor
They are:
i. It allocates sufficient amount of memory space for the
ii. It takes an address of the
Syntax-2 for defining an OBJECT:
<Clsname> objname; //object declaration
Objname = new <clsname ()>; //
When an object is declared
members of the class. When the
memory space is created for the
J2SE (Core JAVA) Notes
:
()>
class. Objname represents JAVA valid variable name
operator.
constructor. The new operator will perform two standard actions.
data members
class and stored in the left hand side variable of syntax
:
declaration//
)>; object referencing//
where value is null. Since, there is no memory space for
object is referenced the value of the object
data members of the class.
Page 11
of the class.

<Clsname> objname; //object declaration
Objname = new <clsname ()>; //
When an object is declared
members of the class. When the
memory space is created for the

()>
class. Objname represents JAVA valid variable name
operator.
constructor. The new operator will perform two standard actions.
data members
class and stored in the left hand side variable of syntax
:
declaration//
)>; object referencing//
where value is null. Since, there is no memory space for
object is referenced the value of the object
data members of the class.
Page 11
of the class.
syntax-1.
. data
is not null. Since		Image Created0Down
By: [email protected] On: Wed Jan 29 18:52:40 IST 2014 Question Reputation2 Answer Reputation0 Belt Series Points0 2User Image
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thanks for the reply, but my question whether "s" is object or object reference and what's the difference?Image Created0Down
By: [email protected] On: Thu Jan 30 12:11:33 IST 2014 Question Reputation0 Answer Reputation0 Belt Series Points0 0User Image
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s is the reference variable which refers to the object in the heap memory.
The syntax:
Sample s=new Sample(), here using new keyword is used to create a memory in the heap in which object is stored. "s" is the reference variable. It is stored in stack memory and from stack memory it refers to object in heap memory.		Image Created1Down
By: [email protected] On: Thu Jan 30 16:00:56 IST 2014 Question Reputation0 Answer Reputation359 Belt Series Points0 359User Image
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