Jyotisolanki at 07:15, 12 December 2017

2017-12-12T07:15:48Z

Jyotisolanki at 12:40, 12 November 2017

2017-11-12T12:40:23Z

Jyotisolanki: Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 |Welcome to the Spoken Tutorial on '''Static blocks '''. |- | 00:06 |In this tutorial we will learn: What are '''s..."

2017-09-15T05:56:37Z

Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 |Welcome to the Spoken Tutorial on '''Static blocks '''. |- | 00:06 |In this tutorial we will learn: What are '''s..."

New page

{| border=1
|| '''Time'''
|| '''Narration'''

|-
| 00:01
|Welcome to the Spoken Tutorial on '''Static blocks '''.

|-
| 00:06
|In this tutorial we will learn: What are '''static blocks'''

|-
| 00:10
|How to declare '''static blocks''' and How to use '''static blocks'''.

|-
| 00:16
|Here we are using :'''Ubuntu 14.04''' '''JDK 1 .7''' and '''Eclipse 4.3.1'''

|-
| 00:26
|To follow this tutorial, you must have knowledge of basics of '''Java''' and '''Eclipse IDE'''.

|-
| 00:34
|You should also have the knowledge of '''instance variables, static variables''' and '''static methods in Java'''.

|-
| 00:43
|If not, for relevant '''Java''' tutorials, please visit the link shown.

|-
| 00:48
|Let us learn about '''static blocks.'''

|-
| 00:52
|'''A Static block''' is mostly used for initializing values of '''static variables'''.

|-
| 00:59
|A '''static block''' is declared using the '''static''' keyword.

|-
| 01:03
|'''Static blocks''' are executed when the '''class''' is loaded in memory.

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| 01:08
|If there are '''static blocks''' in a program, they are invoked before '''constructors'''.

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| 01:14
|We cannot access '''instance variables''' inside a '''static block'''.

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| 01:19
|Now, we will switch to '''Eclipse''' and create a new project called '''StaticBlockDemo'''.

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| 01:26
|Inside this project, we will create the necessary '''classes''' to demonstrate the usage of '''Static Blocks'''.

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| 01:33
|Right click on src folder and click '''New-> Class. '''

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| 01:38
|Type the name of the '''class''' as '''StudentEnroll''' and press '''Enter'''.

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| 01:44
|Now type the following code to represent the '''StudentEnroll''' class.

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| 01:49
|Note that there are two '''static variables count''' and '''orgname'''.

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| 01:54
|Now click on '''Source''' -> and select '''Generate Constructor using Fields'''.

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| 02:00
|Delete the '''super''' keyword from the generated code.

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| 02:04
|We want a message to be printed whenever the '''constructor''' is invoked.

|-
| 02:09
|So inside this '''constructor''', type the following code to print “Constructor invoked”.

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| 02:15
|Now we will add a method '''showData'''( ) to this class to print the values of the variables.

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| 02:21
|So type the following code.

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| 02:23
|Now we will add a '''static block''' to initialize the values of '''count''' and '''orgname'''.

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| 02:29
|Type the following code.

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| 02:32
|The variables '''orgname''' and '''count''' are '''static variables'''.

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| 02:36
|This block of code within the curly brackets prefixed by the '''static''' keyword is a '''static block'''.

|-
| 02:42
|This '''static block''' initializes the values for '''count''' and '''orgname''' as '''100''' and '''IITM''' respectively.

|-
| 02:51
|Inside this '''static block''', type the following code to print '''“static block-1 is invoked”'''.

|-
| 02:58
|Now we will add one more '''class''' containing the '''main method'''.

|-
| 03:03
|So right click on the '''default package''', click '''New-> Class''' and then type the name as '''Demo'''.

|-
| 03:11
|Inside this '''class''' we will have the '''main''' method.

|-
| 03:15
|Type '''main''' and then press '''Ctrl+space''' to generate the '''main method'''.

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| 03:21
|We will create an object of '''StudentEnroll class'''.

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| 03:25
|Type the following code to create an object '''s1'''.

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| 03:29
|Now let us invoke the '''showData''' method to print the values.

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| 03:33
|Type '''s1.showData() semicolon'''

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| 03:38
|Now let us run the '''Demo''' program.

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| 03:41
|We can observe that '''static block''' is invoked before the '''constructor'''.

|-
| 03:46
|The values of '''count and orgname''' are initialized as defined in the '''static block'''.

|-
| 03:53
|Now let us go back to the '''StudentEnroll class'''.

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| 03:57
|Let us see what happens if we initialise the value of id inside the '''static block'''.

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| 04:03
|Inside the '''static block''' type, '''id equals IT01 semicolon'''

|-
| 04:10
|We can see that an error comes up.

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| 04:13
|It indicates that an '''instance variable''' cannot be accessed inside a '''static block'''

|-
| 04:19
|Now let us comment this line and proceed further.

|-
| 04:25
|Let us go back to the slides

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| 04:27
|A '''class''' can contain multiple '''static blocks'''.

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| 04:30
|In such a case they are called only once in the order that they appear in the source code.

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| 04:37
|Switch back to '''Eclipse''' to verify it.

|-
| 04:40
|Let us include one more '''static block''' after the existing one.

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| 04:45
|Type the following code.

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| 04:47
|This '''static block''' initializes the values for '''count''' and '''orgname''' as '''200''' and '''IITB''' respectively.

|-
| 04:57
|Inside this '''static block''' type the following code.

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| 05:01
|Now let us run the '''Demo''' program again.

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| 05:04
|From the output, We can verify that the second '''static block''' is invoked after the first.

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| 05:10
|The values of the '''static variables count''' and '''orgname''' are updated by the second '''static block'''.

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| 05:18
|They are '''200''' and '''IITB''' respectively.

|-
| 05:22
|Let us summarize.

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| 05:24
|In this tutorial we have learnt : What is a '''static block'''
How to declare and define a '''static block''' and How '''static blocks''' are invoked and executed.

|-
| 05:37
|For the Assignment, This assignment is a continuation of the '''Static Methods''' assignment.

|-
| 05:44
|Make sure that you have completed the '''Static Methods''' assignment.

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| 05:48
|As before design the class '''CarService''' as specified in this slide.

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| 05:54
|Identify the '''instance variables''' and '''static variables'''.

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| 05:58
|Define a '''constructor''' to initialize the values for '''instance variables'''.

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| 06:03
|Define a '''static block''' to initialize the values of '''static variables'''.

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| 06:08
|Also create a '''Demo''' class containing the '''main method'''.

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| 06:12
|Inside the main method, create a few objects of '''CarService''' and invoke the '''show'''( ) method.

|-
| 06:19
|The video at the following link summarizes the S'''poken Tutorial Project'''.

|-
| 06:24
|Please download and watch it.

|-
| 06:27
|The '''Spoken Tutorial Project''' Team Conducts workshops using spoken tutorials and Gives certificates on passing the online tests.

|-
| 06:35
|For more details, please write to us.

|-
| 06:39
|'''Spoken Tutorial Project''' is funded by the NMEICT, MHRD, Government of India.

|-
| 06:46
|More information on this Mission is available at the link shown.

|-
| 06:50
|This script has been contributed by: '''Dept. of Information Technology, Amal Jyothi College of Engineering'''.

|-
| 06:58
|This is Priya from IIT Bombay. Thanks for joining.

|}

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-|The video at the following link summarizes the S'''poken Tutorial Project'''.
+|The video at the following link summarizes the '''Spoken Tutorial Project'''.
 |-

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-|'''A Static block''' is mostly used for initializing values of '''static variables'''.
+|A ''' Static block''' is mostly used for initializing values of '''static variables'''.
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Java/C3/Static-Blocks/English-timed - Revision history

Jyotisolanki at 07:15, 12 December 2017

Jyotisolanki at 12:40, 12 November 2017

Jyotisolanki: Created page with "{| border=1 || '''Time''' || '''Narration''' |- | 00:01 |Welcome to the Spoken Tutorial on '''Static blocks '''. |- | 00:06 |In this tutorial we will learn: What are '''s..."