Learn how to program in java

[بن دبي]

<font color='#000000'>Sallam to all ....i hope you are all doing great ... and please excuse me for not writing in Arabic becaude i do not have a keyboard with Arabic Letters lables , well i can some time type a paragraph in Arabic if it is so necessary but that takes me so much time. Any how our subject today is Java programming
*Many of you have heared about Java and JavaScript
*They are totally different Java is a programming language that gets compiled into bytecode and evaluated in the Microprocessor of the PC
*On the other hand , JavaScript is does not have to be compiled into machine language , but rather it &nbsp;is alanguage that is used to add some dynamic actions to the plain text or graphics in a web site.
* &nbsp; Java was developed by Sun Microsystem Company www.sun.com in 1991 and it wa called OAk at the beginning and then was officially called Java in 1995? Why? it is named so after an island in indonesia called Java
*Java is a platform independent , which means that the java programs can work on any computer so we say:"Compile once and run wherever
*So much for that now , let us get to the taste of it
*why some times we can not open some chat programs in some web sites?<img src="http://oasis.bindubai.com/emoticons/rock.gif" border="0" valign="absmiddle" alt='???'>? think wi th me....mmmmmm..well those programs are basically Java Applets and out IE == Internet Explorer does not support some Applets because Microsoft got in conflict with Sun and it has no licence for Java releases from 1.1.8 and onward
*so how would we get it running in our machines well you need to install one of the releases and i recommond 1.4 so go to www.java.sun.com and then downloads and chose 1.4 and go through the process of downloading
* aha and now we have it on our machines but that is not all you have to set the path....the instructions are there also but for XP whih i am using ...you would go t o control panel> system< advanced and the to environment variables< and then double click path and then at the end put ;C:&#92;....the path&#92;jdk..the version you have installed&#92;bin
* for the jdk.... you can just copy the name of the folder created by the installer
.........that is it for now i will give you time to install it and i will be avaliable to answer any question and a fter you are done with setting up the software we will start programming insha&#39;ALLAH

Note: Copyright ---- any one can copy and use what i wrote above and if some one can translate it in Arabic to help other members that will be great...so take your time</font>

[بن دبي]

<font color='#000000'>No Body is interested ....yeah the layout is kind of awful and the laguage is kindaa difficult and there are some mistyoped words ....but at any case i will give you more time....waiting to hear from you brothers and sisters
SalLam</font>

[فتاه من الشرق]

<font color='#E77471'><div align="left"> السلام عليكم اخوويه...
i wish to learn java script, well i&#39;m going to learn it very soon, as i&#39;m studying programming and this is my second year..
but the problem is that i cannot download any more programs, coz i have a problem with my pc.. its very slaw and doesnt have space to download more programs <img src="http://oasis.bindubai.com/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>
but go a head brother, its really an interesting subject..

inshallah as soon as i change my pc, i&#39;ll come back in this topic and download the program and follow up with you>>> <img src="http://oasis.bindubai.com/emoticons/down.gif" border="0" valign="absmiddle" alt=':dd:'>
</div>
<div align="left">thanx alot brother,,
good luck</div></font>

[بن دبي]

<font color='#000000'>public class MyFirstClass
{
public static void main( String [] args)
{
system.out.println(“Hello World”);
}
}

Now go to your MS-DOS command prompt from start> run > and then type in command or cmd and you will see something like this this:



public class MyFirstClass
{
public static void main( String [] args)
{
system.out.println(“Hello World”);
}
}

Now go to your MS-DOS command prompt from start> run > and then type in command or cmd and you will see something like this this:



where I erased my name. There are two backslashes which means we are two folders inside the C: directory so we basically type “cd ../../” that is 2 slashes with 2 dots after each one and that command will take us two levels up and now we are in the C directory. Suppose we named the directory in which we save our java files as “JavaClasses” so we will type : “cd JavaClasses” and note it is case-sensetive. The we will type

javac MyFirstClass.java à this is to compile the code and this will generate a the

MyFirstClass.class file which we will use for running the program so go and check the

JavaClass Directory to find the above named “.class” file

To Run the program type in :

java MyFirstClass -à this time we did not add the suffix “.class” because java

compiler will look at the “file_name.class” so we just need to provide the “.class” file

name without adding the suffix to it and there is another difference ; the first command

javac MyFirstClass.java has the letter c attached to it which tell s that is compiling

a compilation process. AS a result every one should get this output below :



I hope you enjoy it and if you have any question just ask?&#33; Sallam now

if the images do not show up plz double-click themand go tp properties and then copy their location and paste it into a new IE window</font>

[بن دبي]

<font color='#000000'>Sorry guys
those pictures never showed up coz the admin says that i am not allowed to upload those kind of pictures i do not know why is that??? any body can contact the admin and tell him that those ppictures are from the MS-Dos command</font>

[رويان]

<font color='#000000'><div align="center">السلام عليكم والرحمه ...

اولا sankUoo على هالموضوع <img src="http://oasis.bindubai.com/emoticons/woman1.gif" border="0" valign="absmiddle" alt=':wom:'>

ثانيا .. بالنسبة للمشكلة :
انت لما تسوي up load للصوره..
بعد الـ jpg او الـ gif موجود عندك دوت ..
المفروض تشيلها حتى يكون موقع الصوره صح ..

<img src="http://oasis.bindubai.com/download/c1.jpg" onload = "javascript:if(this.width > (screen.width/2)){this.width = (this.width/2)}" onclick="javascript:if(this.width > (screen.width/2)){this.width = (this.width/2)} else {this.width = (this.width*2)}" border="0" alt='Posted image: Click to resize'>


<span style='color:red'>ثالثا والاهم ..

يا ليت تشرح الـ classes وتحط تطبيقات عليها .. <img src="http://oasis.bindubai.com/emoticons/man4.gif" border="0" valign="absmiddle" alt=':man:'> </span>

ويسلمو على هالموضوع ..

<img src="http://oasis.bindubai.com/emoticons/love.gif" border="0" valign="absmiddle" alt=':lo:'>

...</div></font>

[بن دبي]

<font color='#000000'>Thanx for the help and the reminder Sara

Well i was gonna go over these things just after getting

the signal of acceptance of this subject...and here it

lights up by your and Fatat al Sharq&#39;s Comments

What does the every typical code consist of

1/Class : Unlike other programming languages , Java

Require the user to put the code withen a class named

by him/herself.....so what is a class ...it is basically a

name and it is the basic element of any java program

and every other thing is to be included inside it

the one i provided above is named MyFirstClass...and

here is one more thing .... the name of the class must

match the name of the file that contains your code

so if you named the file as BinDubai.java you will have

to start your code with &nbsp; public class BinDubai

and that is the first line of code in every program you

write....the comes the { or the curly bracket

which will have to be closed with another } at the very end
of your code which means that every other thing inside

those brackets belongs to the BinDubai class ...that is

all for class for now

then comes another very important thing

the main method or....public static void main(String [ ] args)

that is the place where the program will start excution

or will basically will give you some thing and then {

this means this is the start of the main method and

as well as for the class it has to be closed with another}

for the time being we want to just print a message saying

Sallam To All Members in BinDubai

so what we will do that we will type

System.out.println("Sallam To All Members in BinDubai");

and notice that every statement has to end with a ;

and every statement is case-sensetive so follow what

is written exactly but not for the closing (( because this

writing panel is Arabic oriented so it does not show it

correctly as it is suppose to be in English()

so now from the experience in the first lesson and this

one , you dhould be able to write a prgram that prints

a welcome message in MS-DOS command window

so try this one

public class BinDubai &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}
public static void main(String [ ] args) ;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}
System.out.println("Hello Bindubai members");

&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;{
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
{



Note : if you are really interested in learning the language

i will work with you step-by-step insha&#39;ALLAH so do not

hesitate to ask any question at any time .....my e-mail is

qmaqma@hotmail.com...i check it almost every two

hours while i am awake ...so send any question or

problem and expect the answer to be in English

because i do not have ArabicKeyboard now , but i can

read and understand Arabic much better than English

So excuse me once again

Finally, if somebody feels this is useless or meaningless

please let me know and i will stop it imeadiately and we

can switch to learn another language like SQL or HTML

Sallam To All now.....................:)</font>

[رويان]

<font color='#000000'>..

صقر تسلم على الشرح ..

طيب انت سو سكب لكل شي وخلك على الكلاسز <img src="http://oasis.bindubai.com/emoticons/lookaround.gif" border="0" valign="absmiddle" alt=''>

سؤال &nbsp;كيف استخدم الـ &nbsp;set and get methods في الكلاس نفسه ...وهل من الضروري اصلا اني استخدمها ؟

وبعدين لما نسوي import &nbsp;للكلاسات شو الفرق بين الـ core pagage والـ extension pakkage

<img src="http://oasis.bindubai.com/emoticons/blush.gif" border="0" valign="absmiddle" alt=':b:'>

والبقية آتية &nbsp;<img src="http://oasis.bindubai.com/emoticons/devil.gif" border="0" valign="absmiddle" alt=':de:'>

<img src="http://oasis.bindubai.com/emoticons/pirate.gif" border="0" valign="absmiddle" alt=':por:'></font>

[بن دبي]

<font color='#000000'>Ok sure Sara

every program can work with out a set, also called mutator, or a get , also called accessor, methods

but we need them if we want to make our attributes or global variables as private so we want to provide a way to other classes using this calss to acces the variables and change them or get their value so we use accessor and mutator which are easy methods

* Get method:
public variabletype get<span style='color:red'>VariableName</span>()
}

return <span style='color:orangered'>variablename</span>;
}

for the Mutator or the set

public void setVariableName(variabletype anewvariablename)
}

variableName = anewvariablename;
{

i never heared of those type of packages but i would think that a core package is when you type like

import java.util.*;
this way you imported every class in the java.util package and you just use whatever class you want .... and that is what i always do because it saves me time and effort to write an import statement for each class i use

and for the extension package i think it would be like import java.util.StringTokenizer;

which only imports the StringTokenizer class

so that is how i understand it but in case i did understand it wrong just let me now and give me examples so i can inshaALLAH explain more

Good Questions Though
GOOD LUCK</font>

[بن دبي]

<font color='#000000'>Oh sorry i guess i got it now

Let us say java.util

That is two packages the core one is java and the util is

the extension package because util resides inside the java package...it is basically a matter of path

package so that is why is called like that

Good Luck</font>

[رويان]

<font color='#000000'><div align="center">السلام والرحمه ..

هذي امثلة على الـ core والـ extension
pakages

<img src="http://oasis.bindubai.com/download/j0.jpg" onload = "javascript:if(this.width > (screen.width/2)){this.width = (this.width/2)}" onclick="javascript:if(this.width > (screen.width/2)){this.width = (this.width/2)} else {this.width = (this.width*2)}" border="0" alt='Posted image: Click to resize'>




وبالنسبة للجزء النظري .. ماشي معاي بس المشكلة لما تجيني مسألة اخبصها من الخاطر ..

فلو تحط مسألة و حلها كمثال لاجل اناقشك فيه اكون شاكره لك .. <img src="http://oasis.bindubai.com/emoticons/blush.gif" border="0" valign="absmiddle" alt=':b:'>

السموحه .. <img src="http://oasis.bindubai.com/emoticons/blush.gif" border="0" valign="absmiddle" alt=':b:'>

</div></font>

[بن دبي]

<font color='#000000'>Well as i told i never had aquestion in an exam or by any

body else about this , so i can not give you examples:dd:

but if you can bring the question , i promise that i will try

my best to solve it

At the end, after seeing your example i came with this eplanation

Core Packages: are packages provided by sun MicrosSystem and that are necessary for Java language to function like the one you had above

Extension Packages: they are packages developed by another user or company for a special purpose like the robocode package developed by IBM and you youself can actually creat your own package and do import using the sataement package packagename; which goes in the first line of any class to be included in that particular package ..... Also Extension packages incluede packages developed by Sun Microsystems itself like the one you provided javax.swing.*;

because the classes in this package do the same work as the the java.awt.*;
classes actually do and so we can call

javax.swing as an <span style='color:red'>extention</span>of the java.awt package

and so on you can find other packages developed by Sun which realy do the same thing as other older packages do but with some improvements and i do not think there is a way in which you can tell if this package is a core one or an extension one from just looking at its name:D ....so you gotta study and see more examples

Finally i am really impressed by these question .. they are

really excellent question

Thanx alot</font>

[أسير الذكريات]

<font color='#810541'>Salaam brother Saqer. Actually I am studying java this semester. I am having a difficult time understanding it. It seems very challenging to me. Probably my teachers are not so good in explaining it. Whenever I have an assignment, I spend so much time in front of the computer trying to figure out how to do it. For example, this Friday we have a program due. We have to use around 9 classes to do this program. I have started it but I got to a point where I can not move further. If you want, I can send you a copy of my work to look at it. It really confuses me especially when I get these weired exceptions. I hope I can understand it one day, and if you are interested in looking at my assignment, send me your email and I will send it to you
Take care buddy

أسير الذكريات</font>

[رويان]

<font color='#000000'>السلام والرحمه ..

<img src="http://oasis.bindubai.com/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':cra:'>

خلونا نتكلم عن الـ user defined class

وهذا اللي كنت اقصده بالمثال ..

ان يكون المطلوب انك تسوي كلاس يحتوي على كذا methods ..

..</font>

[بن دبي]

<font color='#000000'>I apologize for being late in responding . It is the

difference in time since i go to school &nbsp; outside the country

Anyway Brother Aseer send me the problem statement and the code you have developed and i will do my best to solve it

my e-mail is : QMAQMA@hotmail.com

Sara....i will come to your question later insha&#39;ALLAH</font>