Ashwini at 11:02, 22 January 2014

2014-01-22T11:02:23Z

Chandrika: Created page with ''''Title of script''': Getting started with java: first program. '''Author: Prathamesh Salunke''' '''Keywords: video tutorial, Hello World, first program''' {| style="border…'

2012-11-27T10:04:35Z

Created page with ''''Title of script''': Getting started with java: first program. '''Author: Prathamesh Salunke''' '''Keywords: video tutorial, Hello World, first program''' {| style="border…'

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'''Title of script''': Getting started with java: first program.

'''Author: Prathamesh Salunke'''

'''Keywords: video tutorial, Hello World, first program'''

{| style="border-spacing:0;"
! <center>Visual Cue</center>
! <center>Narration</center>

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 1

Opening slide
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Welcome to the Spoken Tutorial on getting started with the '''First java program'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 2

Learning Objectives
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In this tutorial we will learn

<nowiki>* To create a simple java program. </nowiki>

<nowiki>* To compile the program.</nowiki>

<nowiki>* To run the program.</nowiki>

<nowiki>* About the naming conventions followed.</nowiki>

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 3

System Requirements
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Here we are using

* Ubuntu version 11.10 and
* Java Development Environment jdk 1.6

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 4

Prerequisite
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| To follow this tutorial '''JDK 1.6 '''must be installed on your system.

If not, for relevant tutorial please visit our website as shown.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch to '''Terminal''' and then to the '''Text''' '''Editor'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us now write our first java program.

For that you need a '''Terminal''' and a '''Text''' '''Editor'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''gedit'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| I am using '''gedit''' as my '''Text Editor'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| type:

class HelloWorld

Highlight HelloWorld

{

}

<nowiki>[ENTER]</nowiki>

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In the text editor, we will first create the class '''HelloWorld'''.

So type '''class HelloWorld'''

'''HelloWorld '''is the name of the class.

Open ''curly bracket''.

Press '''Enter '''and close ''curly bracket''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Highlight {}
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The code inside this block will belong to the class '''HelloWorld'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Click on the Save icon.
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now save the file by clicking on the '''Save '''icon.

It is a good practice to save the file frequently.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Save as Dialog box
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save As Dialog box '''appears.

Browse the location where you want to save the file.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Select Home directory

Create folder Demo.
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Here, in the home directory we will create a folder.

Let us name it as '''Demo'''

Then inside this folder we will save the file.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Type:

HelloWorld.java

type '''HelloWorld '''dot''' java'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In the '''Name''' text-box, type the name of the class.

In java, the name of the class and the file name should be same.

Recall that the class we have created is HelloWorld.

So we will save this file also as HelloWorld dot java

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Highlight .java
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Dot '''java extension is given to a java file.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Click on '''Save'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Then click on '''Save '''button.

So the file is now saved.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| class HelloWorld

{

'''public static void main()'''

'''{'''

'''}'''

}

Highlight '''Main'''

'''<nowiki>main(String arg[])</nowiki>'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Inside the class, we write the '''main''' method.

So type:

'''''public static void main '''within'' ''parentheses '''String''' '''arg''' Square brackets''

'''Main''' method marks the starting point of the program.

We will describe the words public, static, void and String arg in a future tutorial.

Then again, open curly bracket.

Press '''Enter '''and close curly bracket.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Highlight {}
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The code inside these curly brackets will belong to the main method.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

<nowiki>public static void main(String arg[])</nowiki>

{

'''System.out.println();'''

}

Highlight semicolon

'''System.out.println(“My first java program!”);'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We will now write a code to display a line on the '''Terminal'''.

So type '''''System '''dot''' out '''dot''' println''''' parentheses semi-colon

This statement is used to print a line.

In Java, semi-colon is used to terminate a line.

Now let us tell Java what to print.

Within '''''parentheses in double quotes type My first java program exclamation mark'''.''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Click on '''Save''' icon
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us '''Save '''the file by clicking on '''Save''' icon.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch to the '''Terminal'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us go back to the '''Terminal'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| ls

cd Demo

ls
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Make sure that you are in the directory where your '''HelloWorld.java''' file is present.

Remember that I am in my home directory.

We can see that Demo is a subdirectory.

So''''' '''''type''''' cd '''Space''' Demo '''''and''''' '''hit''' Enter'''''

We see the HelloWorld.java file present in the Demo folder.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| javac HelloWorld.java
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, run the command '''''javac '''Space''' HelloWorld '''dot''' java'''''.

This will compile the file that we have created.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| ls
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Alright now the file is compiled as we see no error.

We can see''' '''the''' HelloWorld.class''' file created.

This file can run anywhere.

That is, on any '''Operating System. '''

We do not need java compiler as well.

Hence, java is rightly described as “write once, run anywhere.”

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch back to the '''Terminal'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Go back to the '''Terminal'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Java HelloWorld
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| After successful compilation, run the program using the command,

'''''java '''''(no c) space '''''HelloWorld '''''(no dot java) and hit '''Enter'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Output
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see the output '''My first java program!'''

So we have written our first java program.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Go back to text editor
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us go back to the '''Text Editor'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Delete ;
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, remove the '''''semi-colon '''''which is at the end of the statement.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Click on '''Save'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Click on the '''Save''' icon.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Go to '''Terminal'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us go back to the '''Terminal'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''javac''' '''HelloWorld.java'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Run the command '''''javac '''Space''' HelloWorld '''dot''' java'''''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| HelloWorld.java:5: ';' expected

System.out.println("My first java program")

^

1 error
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The compiler gives an error.

It says, a semi colon is expected on the fifth line.

The up arrow points to the error statement.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch back to the '''Text Editor'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us go back to the '''Text Editor'''.

In Java, all statements are terminated with semicolons.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Type ;
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So go to the fifth line.

At the end of the statement add a semi-colon.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Click on '''Save'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Click on the '''Save '''icon.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch back to the '''Terminal'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us go back to the '''Terminal'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| javac HelloWorld.java
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Run the command '''''javac '''Space''' HelloWorld '''dot''' java'''''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| java HelloWorld
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The file is successfully compiled as we see no errors.

Now, run the program using the command

'''''java''''' space '''''HelloWorld''''' and hit '''Enter'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Output
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see the output '''My first java program!'''

This is how you can handle errors in java.

As the series progresses, we will learn more about the errors.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch to Slides

Slide 4

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We now see what are the naming conventions in java.

* The class name should be in CamelCase.
* Which means each new word begins with an upper case.
* Example: class HelloWorld, class ChessGame.

So, H of hello, W of World are in uppercase.

Similarly C and G of Chess and Game respectively are in uppercase.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 5

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| * The method name should be in mixed case.
* Which means that the first word should begin with a lower case.
* And all new words should begin with an upper case.
* Also the method name should be a verb.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 6
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| * Example: showString(), main(), goToHelp().The variable name should not begin with digits.<br/> Here '''s''' of show is in lowercase and '''S''' of string is in uppercase.
* We cannot use keywords for our class, method or variable name.
* For example: We cannot use keywords like public, private, void, static and many more.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 7

Summary
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So in this tutorial, we have learnt to write, compile and run a simple java program.

We also saw the naming conventions followed in java.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 8

Assignment
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| For self assessment write a simple java program which prints '''Java file name and class name should be same'''.

To know more about the Spoken Tutorial Project

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 9

About Slide
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"|
* Watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial http://spoken-][http://spoken-tutorial.org/What_is_a_Spoken_Tutorial tutorial.org/What_is_a_Spoken_Tutorial]
* It summarises the Spoken Tutorial project

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

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 10

About Slide

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| 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@spoken-tutorial.org

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 11

Acknowledgment
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Spoken Tutorial Project is a part of the Talk to a Teacher project

* 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 http://spoken-tutorial.org/NMEICT-Intro]

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 12

Contributor Slide
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We have come to the end of this tutorial.

Thanks for joining.

This is Prathamesh Salunke signing off.

Jai Hind.

|}

@@ Line 27: / Line 27: @@
 <nowiki>* To compile the program.</nowiki>
-<nowiki>* To run the program.</nowiki> and
+<nowiki>* To run the program</nowiki> and
 <nowiki>* About the naming conventions followed.</nowiki>
@@ Line 278: / Line 278: @@
 | style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| After successful compilation, run the program using the command,
-'''''java '''''(no c) space '''''HelloWorld '''''(no dot java) extension and hit '''Enter'''.
+'''''java '''''(no c) space '''''HelloWorld '''''(no dot java extension) and hit '''Enter'''.
 |-

Java/C2/First-Java-Program/English - Revision history

Ashwini at 11:02, 22 January 2014

Sneha at 05:48, 7 May 2013

Chandrika: Created page with ''''Title of script''': Getting started with java: first program. '''Author: Prathamesh Salunke''' '''Keywords: video tutorial, Hello World, first program''' {| style="border…'