Difference between revisions of "Java/C3/Calling-methods-of-the-superclass/English-timed"

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| In this tutorial, we will learn: * when to use the '''super keyword'''
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| In this tutorial, we will learn:   when to use the '''super keyword'''
  
 
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|* How to call '''methods '''of the '''super class'''
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| How to call '''methods '''of the '''super class'''
  
 
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|* How to invoke the '''constructor '''of the '''super class'''.
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| How to invoke the '''constructor '''of the '''super class'''.
  
 
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| Here we are using:
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| Here we are using: '''Ubuntu Version 12.04''' ,'''JDK 1.7''' ,'''Eclipse 4.3.1'''
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*'''Ubuntu Version 12.04'''
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*'''JDK 1.7'''
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*'''Eclipse 4.3.1'''
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| The '''super''' keyword :
 
| The '''super''' keyword :
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* refers to the '''instance variable''' of the '''parent class.'''  
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* is used to invoke '''parent class constructor'''.
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refers to the '''instance variable''' of the '''parent class,'''
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* is used to invoke '''parent class method.'''
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is used to invoke '''parent class constructor''',
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is used to invoke '''parent class method.'''
  
 
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| Within curly brackets, type:
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| Within curly brackets, type: '''this dot name is equal to name semicolon''' , '''this dot email_address is equal to email_address'''
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'''this dot name is equal to name semicolon'''
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'''this dot email_address is equal to email_address'''
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| Inside the '''getDetails()''' method-  
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| Inside the '''getDetails()''' method- instead of '''getName''', type '''name''' , instead of '''getEmail''', type '''email_address.'''
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instead of '''getName''', type '''name'''
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instead of '''getEmail''', type '''email_address.'''
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| In this tutorial, we have learnt:
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| In this tutorial, we have learnt: the '''super keyword ''' ,calling the method of the '''super class '''and invoking constructor of '''super class'''.
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* the '''super keyword '''
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* calling the method of the '''super class '''and
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* invoking constructor of '''super class'''.
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| As an Assignment-
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| As an Assignment-Open the previous assignment. Call the '''Vehicle class run method '''in the '''Bike class.'''
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Open the previous assignment.
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Call the '''Vehicle class run method '''in the '''Bike class.'''
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| The output should be:
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| The output should be: '''The Vehicle is running.''' '''The Bike is running safely.'''
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'''The Vehicle is running.'''
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'''The Bike is running safely.'''
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| The Spoken Tutorial Project Team:
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|The Spoken Tutorial Project Team: Conducts workshops using spoken tutorials
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* Conducts workshops using spoken tutorials
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Gives certificates for those who pass an online test. For more details, please write to '''contact at spoken hyphen tutorial dot org'''.
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* Gives certificates for those who pass an online test.
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For more details, please write to '''contact at spoken hyphen tutorial dot org'''.
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| More information on this mission is available at:
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| More information on this mission is available at: '''http://spoken-tutorial.org/NMEICT- Intro'''
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'''http://spoken-tutorial.org/NMEICT- Intro'''
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Latest revision as of 10:36, 3 May 2019


Time
Narration
00:01 Welcome to the spoken-tutorial on Calling methods of the super class.
00:07 In this tutorial, we will learn: when to use the super keyword
00:13 How to call methods of the super class
00:17 How to invoke the constructor of the super class.
00:22 Here we are using: Ubuntu Version 12.04 ,JDK 1.7 ,Eclipse 4.3.1
00:32 To follow this tutorial, you must have basic knowledge of Java and Eclipse IDE.
00:39 You must also have knowledge of subclassing and method overriding in Java.
00:45 If not, for relevant tutorials, please visit our website.
00:51 A subclass can use a superclass data or method using the super keyword.
00:58 The super keyword :

refers to the instance variable of the parent class,

is used to invoke parent class constructor,

is used to invoke parent class method.

01:13 Now, let us go to the IDE and to the project we created earlier.
01:19 Let us go to the Manager class.
01:22 Now, come to the getDetails() method.
01:26 In the return statement, let us remove Name and Email.
01:32 Now, let us come to the Employee class.
01:36 This is the parent class or super class.
01:41 We already have a getDetails() method here.
01:46 This method returns the name and email.
01:51 So, we can use this getDetails() method in the Manager class.
01:57 We will call getDetails() method from the Employee class, inside the Manager class.
02:04 So, come to the getDetails() method in the manager class.
02:10 Inside the return statement, type: super dot getDetails() plus slash n Manager of getDepartment().
02:22 Now, let me run the program.
02:25 We can see that we get the Manager details. Thus we can call the method of superclass inside the subclass.
02:36 Now let us come to the Employee class.
02:41 Let us include a constructor here.
02:44 So, inside the Employee class, type: public space Employee within brackets String name, String email_address .
02:59 Within curly brackets, type: this dot name is equal to name semicolon , this dot email_address is equal to email_address
03:17 Now, let us comment the setter and getter methods.
03:23 Inside the getDetails() method- instead of getName, type name , instead of getEmail, type email_address.
03:37 A subclass inherits all of the methods and variables from a parent class.
03:44 Note that it does not inherit constructors.
03:49 But, constructors can call the non-private constructors of its superclass.
03:55 We do this using the keyword super from the child class constructor.
04:01 We will see that now.
04:04 For that, come to the Manager class. We will include a constructor here.
04:10 So, type: public space Manager within brackets String space name comma String space email underscore address comma String space dept .
04:30 Then, within curly brackets, type: super within brackets name, email underscore address semicolon.
04:44 Then type: department is equal to dept semicolon.
04:51 Here we will comment the setter and getter methods.
04:56 Then, in the getDetails() method type: department instead of getDepartment.
05:05 Now, come to the TestEmployee class.
05:09 Comment the call to the setter methods.
05:15 Now, inside the call to the Manager constructor, type: within quotes Nikkita Dinesh, abc@gmail.com, Accounts.
05:32 Now, run the program.
05:35 We get the output as shown. We get the Manager details.
05:40 In this way, we can call the constructor of the super class.
05:45 In this tutorial, we have learnt: the super keyword ,calling the method of the super class and invoking constructor of super class.
05:56 As an Assignment-Open the previous assignment. Call the Vehicle class run method in the Bike class.
06:04 The output should be: The Vehicle is running. The Bike is running safely.
06:10 To know more about the Spoken Tutorial Project, watch the video available at the following link.
06:17 It summarizes the Spoken Tutorial project . If you do not have good bandwidth, you can download and watch it.
06:26 The Spoken Tutorial Project Team: Conducts workshops using spoken tutorials

Gives certificates for those who pass an online test. For more details, please write to contact at spoken hyphen tutorial dot org.

06:42 Spoken Tutorial Project is a part of the Talk to a Teacher project.
06:46 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
06:54 More information on this mission is available at: http://spoken-tutorial.org/NMEICT- Intro
07:05 This is Arya Ratish from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

Jyotisolanki, PoojaMoolya, Pratik kamble, Sandhya.np14

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