Difference between revisions of "Java/C2/First-Java-Program/English-timed"

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|Alright now Let us  write our first java program.
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|Alright now l et us  write our first java program.
  
 
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|  In the text editor, we will first create the class '''HelloWorld'''.  
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|  In the '''text editor'''  , we will first create the class '''HelloWorld'''.  
  
 
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|Let us name it    '''Demo''' and press enter
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|Let us name it    '''Demo''' , press''' enter'''
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|So we will save the file  as HelloWorld dot java
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|So we will save the file  as''' HelloWorld dot java'''
  
 
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|We will describe  public, static, void and String arg in a future tutorial.
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|We will describe  '''public, static, void and String arg'''  in a future tutorial.
  
  
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|Now let us tell Java what to print.
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|Now let us tell Java,  what to print.
  
  
 
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| So Within '''''parentheses in double quotes type My first java program exclamation mark'''.''
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| So Within '''''parentheses in double quotes type, My first java program exclamation mark'''.''
  
 
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|  Let's go  to '''Terminal'''.
  
 
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|We see   HelloWorld.java file present in the Demo folder.
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|We see ''' HelloWorld.java''' file present in the Demo folder.
  
 
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| Lets compile this file so type  '''javac '''Space''' HelloWorld '''dot''' java''''' and hit enter  
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| Lets compile this file so type  '''javac '''Space''' HelloWorld '''dot''' java''''' and hit''' enter'''
  
  
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|We can see     '''HelloWorld.class''' file created.
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|We can see '''HelloWorld.class''' file created.
  
 
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|  After successful compilation, run the program using the command,  
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| So After successful compilation, run the program using the command,  
  
 
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|So we have written our first java program.Let us go back to editor
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|So we have written our first java program.Let us go back to '''editor'''
  
 
   
 
   
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|  Click on the '''Save '''icon. It is necessary tosave the file before compiling
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|  Click on the '''Save '''icon. It is necessary to save the file before compiling
  
 
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|Now, run the program using the command  '''''java'''''  '''''HelloWorld''''' and  .
 
|Now, run the program using the command  '''''java'''''  '''''HelloWorld''''' and  .
  
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|So, H of hello and  W of World are in uppercase.
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|So,''' H''' of hello and  '''W''' of World are in uppercase.
  
  
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|   Example: showString(), main(), goToHelp() Here '''s''' of show is in lowercase while  '''S''' of string is in uppercase .The variable name should not begin with digits.<br/>.
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| For    Example: showString(), main(), goToHelp(). Here '''s''' of show is in lowercase while  '''S''' of string is in uppercase .The variable name should not begin with '''digits''' .  
 
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|For example:  cannot use keywords like public, private, void, static and many more.  
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|For example:  cannot use keywords like''' public, private, void, static and many more'''.  
  
  
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| If you do not have good bandwidth, you can download and watch it  
 
| If you do not have good bandwidth, you can download and watch it  
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Revision as of 15:29, 24 June 2013

Time' Narration
00:02 Welcome to the Spoken Tutorial on getting started with the First java program.
00:09 In this tutorial we will learn
00:11 To create a simple java program.
00:14 To compile the program.
00:16 To run the program. and
00:19 About the naming conventions followed in java
00:24 Here we are using Ubuntu version 11.10 and Java Development Environment jdk 1.6


00:32 To follow this tutorial JDK 1.6 must be installed on your system.
00:39 If not, for relevant tutorial please visit our website which is as shown.
00:46 Alright now l et us write our first java program.
00:51 For that you need a Terminal and you need a Text Editor.



00:56 I am using gedit as my Text Editor
01:01 In the text editor , we will first create the class HelloWorld.
01:06 So type class HelloWorld HelloWorld is the name of the class.


01:17 And Open curly bracket. Enter and close curly bracket.



01:24 The code between this two curly brackets will belong to the class HelloWorld
01:33 Now save the file by clicking on Save icon at the top
01:37 It is a good practice to save the file frequently.
01:43 soSave As Dialog box appears.
01:46 Browse the location where you want to save your file.
01:51 Here, in the home directory i will create a folder.
01:57 Let us name it Demo , press enter
02:02 Then inside this folder we will save the file.
02:08 In the Name text-box, type the name of the class.
02:13 In java, the name of the class and the file name should be same.
02:20 Recall that we created class HelloWorld.


02:25 So we will save the file as HelloWorld dot java
02:33 Dot java is the file extension given to the java file.
02:39 Then click on Save button. So the file is now saved.
02:47 Inside the class, we write the main method.


02:53 So type:
02:54 public static void main parentheses inside parentheses String arg Square brackets


03:10 Main functions marks the starting point of the program.


03:15 We will describe public, static, void and String arg in a future tutorial.


03:23 Then once again, open curly bracket.
03:27 Press Enter and close curly bracket.



03:32 The code between these two curly brackets will belong to the main method.
03:41 We will now write a code to display a line on the Terminal.


03:46 So inside main method typeSystem dot out dot println parentheses semi-colon


03:59 This is the statement used to print a line. semi-colon is used to terminate a line.


04:10 Now let us tell Java, what to print.


04:13 So Within parentheses in double quotes type, My first java program exclamation mark.
04:30 Let us Save the file by clicking on Save icon.
04:36 Let's go to Terminal.
04:38 Make sure that you are in the directory where you save your HelloWorld.java


04:46 Remember that I am in my home directory.


04:50 So type cd Space Demo and hit Enter


04:59 We see HelloWorld.java file present in the Demo folder.
05:06 Lets compile this file so type javac Space HelloWorld dot java and hit enter


05:21 This compile the file that we have created.
05:25 Alright now the file is compiled as we see no error.
05:30 We can see HelloWorld.class file created.
05:36 This file can run anywhere.
05:38 That is, on any Operating System.
05:41 We do not need java compiler as well.
05:45 Hence, java is rightly described as “write once, run anywhere.”


05:51 So After successful compilation, run the program using the command,
05:56 java (no c) space HelloWorld (no dot java) extension and hit Enter.
06:07 You will get the output My first java program!
06:13 So we have written our first java program.Let us go back to editor


06:22 Now, remove the semi-colon which is at the end of the statement.
06:27 Click on Save icon.
06:29 Let us go back to the Terminal.
06:33 Run the command javac HelloWorld dot java.
06:41 The compiler gives an error.
06:44 It says, a semi colon is expected on the fifth line.


06:52 The up arrow points to the error statement.
06:57 Let us go back to the Editor.
07:01 In Java, all statements are terminated with semicolons.
07:06 So go to the fifth line and add a semicolon.


07:13 Click on the Save icon. It is necessary to save the file before compiling
07:22 Let us go back to the Terminal.
07:25 Compile the file using javac Space HelloWorld dot java.
07:32 The file is successfully compiled as we see no errors.
07:36 Now, run the program using the command java HelloWorld and .


07:45 We see the output My first java program!
07:49 This is how you handle errors in java.
07:54 As the series progresses, we will learn more about the errors.
08:02 We now see what are the naming conventions in java.
08:06 * class name should be in CamelCase.
08:10 * Which means each new word begins with an upper case.
08:14 * Example: class HelloWorld, class ChessGame.
08:19 So, H of hello and W of World are in uppercase.


08:25 Similarly C and G of Chess and Game respectively are in uppercase.
08:31 The method name should be the mixed case.
08:35 Which means that the first word should begin with a lower case.
08:39 And all new words followed should begin with an upper case.
08:44 Also the method name should be a verb.


08:48 For Example: showString(), main(), goToHelp(). Here s of show is in lowercase while S of string is in uppercase .The variable name should not begin with digits .
09:06 We cannot use keywords for our class, method or variable name.
09:13 For example: cannot use keywords like public, private, void, static and many more.


09:22 So in this tutorial, we have learnt to write, compile and run a simple java program.
09:30 We also saw the naming conventions followed in java.
09:35 For self assessment write a simple java program to prints Java file name and class name should be same.


09:47 To know more about the Spoken Tutorial Project
09:50 Watch the video available at http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
09:58 It summarises the Spoken Tutorial project
10:02 If you do not have good bandwidth, you can download and watch it
10:08 The Spoken Tutorial Project Team
10:10 Conducts workshops using spoken tutorials
10:13 Gives certificates for those who pass an online test
10:17 For more details, please write to contact@spoken-tutorial.org


10:25 Spoken Tutorial Project is a part of the Talk to a Teacher project
10:30 It is supported by the National Mission on Education through ICT, MHRD, Government of India
10:38 More information on this Mission is available at 
http://spoken-tutorial.org/NMEICT-Intro


10:49 We have come to the end of this tutorial.
10:51 Thanks for joining.
10:53 This is Prathamesh Salunke signing off. Jai Hind.
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