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2015-12-23T04:39:14Z

Created page with "'''Title of script:''' Abstract Classes '''Author:''' Joms Antony '''Keywords:''' Abstract Methods, Concrete Methods, Abstract Classes, Concrete Classes, Inheritance, Method..."

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'''Title of script:''' Abstract Classes

'''Author:''' Joms Antony

'''Keywords:''' Abstract Methods, Concrete Methods, Abstract Classes, Concrete Classes, Inheritance, Method Implementation, Video tutorial, java tutorial

{| style="border-spacing:0;"
| style="background-color:#ffffff;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| <center>'''Visual Cue'''</center>
| style="background-color:#ffffff;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| <center>'''Narration'''</center>

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 1:'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Welcome to the Spoken Tutorial on''' Abstract Classes.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 2:'''

'''Learning Objectives'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| In this tutorial we will learn about:

* '''Abstract Methods '''and''' Concrete Methods'''
* '''Abstract Classes '''and''' Concrete Classes '''and
* How to use '''Abstract Classes'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 3:'''

'''Software Requirements'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| For this tutorial, I am using

* '''Ubuntu 12.04'''
* '''JDK 1.7 '''and
* '''Eclipse''' '''4.3.1'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 4:'''

'''Prerequisites'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| To follow this tutorial, you should have knowledge of basics of''' Java''' and''' Eclipse IDE.'''

You should also have the knowledge of''' subclassing '''in''' Java.'''

If not, for relevant''' Java '''tutorials, please visit the link shown.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| First we will see about '''Abstract Method'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 5:'''

'''What is an Abstract Method?'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| An '''Abstract method''' is a''' '''method that is declared without implementation.

It''' '''is declared using''' abstract '''keyword

There should not be opening and closing parenthesis for this method.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 6:'''

'''Abstract Method'''

'''Example:'''

Highlight the method and '''abstract''' keyword
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The''' method showDetails()''' illustrated here, is an example of''' abstract method'''.

Note that this''' '''method is declared using the''' abstract '''keyword with no current implementation.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Next we will see about '''concrete method'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 7:'''

'''Concrete Method:'''

'''Example:'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| A '''Concrete''' '''method''' is completely implemented within the curly brackets.

This method''' showBasicDetails()''' illustrated here is an example of '''concrete method'''.

Observe that this method is implemented completely.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now we will learn about '''abstract class''' with an example.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 8:'''

'''Abstract Class:'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| An''' abstract class''' usually contains at least one''' abstract method'''.

'''Abstract methods '''can be added only to '''abstract classes.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 9:'''

'''Abstract Class - Example'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The '''class Person''' illustrated here is an''' abstract class.'''

It contains an''' abstract method''' called''' showDetails()'''.

It can also contain '''variables''' and other '''concrete methods.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 10:'''

'''Abstract Class - Example'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The figure here represents an inheritance relation.

Here, the''' Person class''' is an''' abstract class.'''

The''' Employee class''' and''' '''the '''Student class''' are subclasses of''' '''the''' Person class'''.

These subclasses can provide their own different implementations.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Go back to '''Slide 9 '''and point the '''showDetails() '''method

Switch to '''Slide 10'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| These are done by''' showDetails( ) method''' present in the''' Person class.'''

For example:

'''ShowDetails() Method''' in the''' Employee class''' prints the '''Employee ID''' and''' '''the''' Salary''', where as

'''ShowDetails() Method''' in the''' Student class''' prints the '''Student Reg No''' and''' '''the '''Grade.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 11:'''

'''Concrete Class:'''

'''ExampleSlide 10'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| A''' '''class is said to be a''' concrete class,''' if all the methods in that class are''' concrete methods'''.

The '''class Employee''' illustrated here is a''' concrete class'''.

All the methods inside this class including''' showDetails()''' are concrete.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Let us understand the usage of '''Abstract class '''with a sample program.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| In Ecilpse IDE a project called '''AbstractDemo''' is created,

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now we will switch to''' Eclipse''' and create a new project called '''AbstractDemo'''.

Inside this project we will create the necessary classes to demonstrate the usage of''' Abstract class.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Create the''' class Person''' in the '''src''' folder.

Type

'''String name;'''

'''int age;'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now, right click on '''src''' folder and click '''new-'''> '''class'''.

Type the name of the class as '''Person''' and press '''Enter'''.

Now we will add the fields to represent the name and age of the''' Person'''.

Type''' String name semicolon.'''

Also type''' int age semicolon.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| click on''' source ->''' and select''' generate constructor using fields'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now click on''' source ->''' and select''' generate constructor using fields. '''

Delete the '''super '''keyword''' '''from the generated code.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Constructor''' code
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| This '''constructor''' can initialise the values of '''name''' and '''age '''fields'''.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type

'''public void showBasicDetails( )'''

{

System.''out''.println("Name:"+name);

System.''out''.println("Age:"+age);
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| We will add a''' concrete method''' to this '''class''' to print the name and age.

So type '''public void showBasicDetails( ).'''

Within brackets type,

'''System.''out''.println''' within round brackets and within quotes type''' Name''' colon plus''' name''' semicolon

Also type

'''System.''out''.println''' within round brackets and within quotes''' Age''' colon plus''' age''' semicolon

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type

'''public void showDetails( )'''<nowiki>;</nowiki>

Point to the error
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now we will add an '''abstract method''' to this '''class'''.

So type '''public void showDetails( )''' semicolon.

An error comes up, since we have not yet added the''' abstract '''keyword.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type the keyword''' abstract'''

| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| So now add the keyword '''abstract.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Point to the error

Type the keyword''' abstract'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now we can see another error comes up.

This is because, '''abstract methods''' can be added only to '''abstract''' '''classes'''.

So now add the keyword''' abstract''' to the''' Person class '''to make it an''' abstract class.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Right click on the '''default package''' and create another''' class''' called''' Employee.'''

Type''' extends Person'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Then right click on the '''default package''' and create another''' class''' called''' Employee.'''

Now to make this a subclass of '''Person class, '''type''' extends Person'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Point to the error message
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now we can see an error comes up in the '''Eclipse IDE.'''

It indicates that, we should provide an implementation to the '''abstract method''' '''showDetails( )'''.

We will do it a little later.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type''' '''

'''String empid semicolon;'''

'''int salary;'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now create two fields to represent the employee id and employee salary.

So type''' String empid semicolon'''

and''' int salary semicolon'''<nowiki>;</nowiki>

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| click on '''source'''-> and select''' generate constructor using fields'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now click on '''source'''-> and then select''' generate constructor using fields.'''

This '''constructor''' can initialise the values of '''name, age, empid '''and''' salary'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type

'''public void''' showDetails()

{

System.''out''.println("Emp id"+empid);

System.''out''.println("Salary:"+salary);

'''}'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Let us now define the''' showDetails''' '''method'''.

So type''' public void showDetails( ).'''

Inside this method, we need to print the employee details.

So type

'''System.''out''.println''' within quotes''' Emp id''' colon plus''' empid''' semicolon

'''System.''out''.println''' within quotes''' Salary''' colon plus''' salary''' semicolon

Note that the error disappears, once the '''showDetails() method''' is implemented.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Next we will see a '''Student class''' of the project.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Show and highlight the code for Student Class.
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| I have already created a subclass called''' Student'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight the''' regno''' and''' grade''' fields
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| There are two fields in the '''Student class, regno''' and''' grade''' which represent student reg. no and grade.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight''' constructor'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| A '''constructor''' is also created inside this class.

This '''constructor''' can be used to initialize the values for''' name, age, regno '''and''' grade.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight the code

'''public void''' showDetails()

{

System.''out''.println("Student regno:"+regno);

System.''out''.println("Student grade:"+grade);

}
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The''' showDetails''' method is also implemented in this class.

It prints the values of''' Student Reg. Number''' and''' grade'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight''' showDetails()''' method of''' Employee class'''

Highlight''' showDetails()''' method of''' student class'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now note that the''' Employee''' class has its own implementation of''' showDetails().'''

And the''' Student''' class has its own implementation of''' showDetails().'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Right click on the '''default package, '''click '''new'''-> '''class''' and then type name as''' Demo'''.
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now right click on the '''default package.''' Click on '''new'''-> '''class''' and then type name as''' Demo.'''

Inside this class we will have the '''main method''',

So type '''main''' and then press ctrl+space to generate the''' main method.'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type

Person p =new Person(“John”);

Point to the error

Remove the line
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now let us try to instantiate the''' Person class''' by typing

'''Person p equals new Person.'''

Within brackets and double quotes type '''John''' and put a semicolon.

Now we can see an error.

This is because the''' Person class''' is '''abstract''' and it cannot be instantiated.

Lets remove this line.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight the code line by line

Person p1=

new Employee("John",40,"E267",10000);

p1.showBasicDetails();

p1.showDetails();

Highlight the code line by line

Person p2=

new Student("Hari",20,"12005",'A');

p2.showBasicDetails();

p2.showDetails();
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Type the following code as displayed on the screen.

Now let us instantiate the''' Person class''' using the''' Employee''' '''class''' as '''Person p1 equals new Employee.'''

In the first line, we are passing the values of different arguments.

'''John''' is passed as '''Employee name''',

'''40''' as the value of '''ageE267''' as the value of '''Employee ID''' and

'''10000''' as the value of '''Employee salary.'''

Now we can invoke the '''concrete method''' in the '''Person class''' as '''p1.showBasicDetails()'''

We can also call the''' showDetails()''' method using the '''object p1''' as '''p1.showDetails()'''

Similarly instantiate the''' Person class''' using the''' Student''' '''class'''.

This is represented as '''Person p2''' '''equals new Student.'''

Now we are passing the values of different arguments.

'''Hari''' is passed as the value of''' student name,''' '''20''' as the value of '''age'''.

'''12005''' as the value of''' student Reg No'''. and

'''A''' as the value of '''grade'''.

Now we can call the''' showBasicDetails()''' '''method '''using the '''object p2''' as

'''p2.showBasicDetails()'''

We can also invoke the''' showDetails()''' '''method''' using the '''object p2''' as

'''p2.showDetails()'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Right click on the ''class'' Demo and then select '''Run as''' -> '''Java Application'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Now let us run this '''Demo''' program.

So right click on the '''class''' '''Demo''' and then select '''Run as''' ->''' Java Application'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| Highlight code and the output
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| We can see the output with the basic employee details like''' name '''and''' age.'''

These are printed by '''showBasicDetails() method.'''

Other Employee details like''' employee ID '''and '''salary '''are printed by the''' showDetails()''' '''method'''.

Similarly the basic student details like '''name''' and '''age''' are printed by''' showBasicDetails() method.'''

Other details of the student like

'''Student reg no '''and '''grade''' are printed by the''' showDetails()''' '''method'''.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"|
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| This brings us to the end of this tutorial. Let us summarize.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 12:'''

'''Summary'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| In this tutorial we have learnt about

* '''Abstract Methods '''and''' Concrete Methods'''
* '''Abstract Classes '''and''' Concrete Classes '''and
* How to create and use''' Abstract Classes'''

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''Slide 13:'''

'''Assignment'''
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| As an''' '''assignment

# Create an '''abstract class''' '''Vehicle''' which contains an '''abstract method''' '''run()'''
# Create a''' '''subclass''' Car''' which''' '''extends''' '''the '''Vehicle''' '''class''' and implements the '''run''' '''method''' that prints

'''“Car is running on 4 wheels”'''

# Also create a''' '''subclass''' Bike''' which again''' '''extends''' '''the '''Vehicle''' '''class''' and implements the '''run''' '''method''' that prints

'''“Bike is running on 2 wheels”'''

# Also create a '''Demo class '''containing the''' main method''' to verify the results.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''About Project'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The video at the following link summarizes the''' '''Spoken Tutorial Project.

Please download and watch it.

|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| '''About Workshops'''

| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"| The Spoken Tutorial Project Team

• Conducts workshops using spoken tutorials

• Gives certificates on passing the online tests

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Java/C3/Abstract-Classes/English - Revision history

Nancyvarkey at 09:11, 12 January 2017

Priyacst at 06:40, 12 January 2017

Nancyvarkey at 04:29, 24 December 2015

Priyacst: Created page with "'''Title of script:''' Abstract Classes '''Author:''' Joms Antony '''Keywords:''' Abstract Methods, Concrete Methods, Abstract Classes, Concrete Classes, Inheritance, Method..."