Difference between revisions of "Java/C2/Creating-object/English"

• Reference Variables
• Constructing objects
• Memory Allocation for objects

• Ubuntu 11.10
• JDK 1.6
• Eclipse 3.7.0

If not please see the spoken-tutorial on these topics available at

spoken hyphen tutorial dot org.

To access the members of a class , we need to create an object for the class.

An object is an instance of a class.

Each object consist of state and behavior.

Recall the example of human being class we had discussed in the earlier tutorial.

Object stores its state in fields or variables.

It exposes its behavior through methods.

We know about the 8 primitive data types in Java.

All other types refer to objects rather than primitives.

Variables that refer to objects are reference variables.

public class TestStudent {

public static void main(String args[]){

Student stud1 = new Student();
}

Highlight each term and explain

Now, let me remove the main method from this class.

Save the file by pressing Control and S keys simultaneously.

Now create another class named TestStudent inside the same project.

I have already created it.

In this class I have the main method.

Inside the main method I will create an object of the Student class.

For that, inside the main method, type

Student space stud1 equal to new space Student opening and closing brackets, semicolon.

Thus we have created an object of the Student class.

Here, Student is the name of the class for which the object is to be created.

stud1 is a reference variable referring to one object of the Student class.

The new keyword allocates space for the new object to be created.

Please note that stud1 is not the object of the Student class.

It only holds the reference of the new object created.

System.out.println(“stud1 contains” + stud1 );

So next line type System dot out dot println within brackets and double quotes stud1 contains plus stud1 and then semicolon.

Now, save and run the file TestStudent dot java.

Here Student is the name of the class of the new object created.

The second part is the memory address of the new object created.

We can access the fields and methods of the Student class using stud1.

We will learn about these in the coming tutorials.

Type Student stud2=new Student();

So, I will type Student space stud2 equal to new space Student opening and closing brackets semi-colon.

Now, let save and run this file.

That is, stud1 and stud2 are referring to two different students.

They have different roll numbers and names.

Type Student stud2=stud1;

Type Student stud2 equal to stud1.

Now, save and run this file.

That is both stud1 and stud2 are referring to the same object with a roll number and name.

• Reference variables
• Creating object using new operator
• Assigning references

• create a class named TestEmployee.
• Create an object of the Employee class
  with reference variable as emp1.

• It summarises the Spoken Tutorial project

• If you do not have good bandwidth, you can download and watch it

• Conducts workshops using spoken tutorials

• Gives certificates for those who pass an online test

• For more details, please write to contact@spoken-tutorial.org

Acknowledgment slide

• It is supported by the National Mission on Education through ICT, MHRD, Government of India
• More information on this Mission is available at
• http://spoken-tutorial.org/NMEICT-Intro

This is Arya Ratish from IIT Bombay signing off.

Thanks for joining us.

• It summarises the Spoken Tutorial project

• If you do not have good bandwidth, you can download and watch it

• Conducts workshops using spoken tutorials

• Gives certificates for those who pass an online test

• For more details, please write to contact@spoken-tutorial.org

• It is supported by the National Mission on Education through ICT, MHRD, Government of India
• More information on this Mission is available at
• http://spoken-tutorial.org/NMEICT-Intro

Thanks for joining us.

This is Arya Ratish signing off.

Good bye and Jai Hind.