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A Web Server takes a Client request and gives something back to the Client.
A web browser lets a user request a resource. The web server gets the request,
finds the resource, and returns something to the Client Sometimes that resouce is an HTML page. Sometimes it's a picture. Or a PDF file(Data). Doesn't matter- the client asks for the resouce and server sends it back.

When we say "server", we mean either the physical machine (hardware) or the web server application (software). Real time example.

Above picture some transaction between Client House and Server House for transportation using Truck(Web Server). Client House need package (Truck Driver taking Request- URL) and pass the information to Server House. In the Server House Workers( Helper - JSP Files, Server side files) load the package into the Truck. It taking back to the Client House.

For Transportation people are using different vehicles(Airbus, Ship, Truck). Same way Web Servers(software) also diffrent products like Tomcate(Open source), Bea Web Logic, IBM Websphere,etc...

When we talk about clients, througn, we usally mean both(or either) the human user and the browse application.

The browser is the piece of software(Firefox or Opera) that knows how to communicate with the server. The browser's other big job is iterpreting the HTML code and rendeing the web page for the user.

HTTP is the protocal Client and Servers use on the web to communicate. The server uses HTTP to send HTML to the client.

The HTTP protocol has serveral methods, but the onew we'll use most often are GET and POST.

GET is te simples HTTP method, and its main job in life is to ask the server to get a resource and send it back. That resource might be an HTML page ,a PDF etc. Doesn't matter. The poing of GET is to Get someting back from the server.

POST is a more powerful request, IT' like a GET plus plus. With POST, we can request something and at the same time send form data to the server.

Web Server softwares having different tree stuctures and defalut port numbers. Weblogic running at http://localhost:7001, Tomcat at http://localhost:8080, IBM Websphere at http://localhost:9080

If you know any information about this topic please comment..

Yesterday i was designed one poster to promote my blog in occasion of two thousand visits i almost caught up after my one month on-line(at this moment my statcounter counter display 5,000 visits). So I am presenting this poster.

Download Original Poster

Please Comment

Inheritance involves creating new classes from the existing ones. it provides the ability to take the data and methods from an existing class and derive a new class. The keyword extends is used to inherit data and methods from a existing class. the extends keyword is used as

class New_Class extends Old_Class { ....... }

The inherited methods and data are those that are declared public or protected inside the super class. Using(Extending) same Engine.

Note: private members are not inherited. Here key is private

Java Access Modifiers Lesson

Eg How Inheritance works.

Download Source
>javac Inheritance.java

>java Inheritance

output:

x value is 10;
y value is 4;
sum is 14;
subtraction is 6;

Note : The object of the sub-class was created inside the main. The class Sub extends the class Add. This ist derives all the protected and public members of the class Add. The class Sub contains a method of it own, Sub_xy()/ The Object of class Sub in the main() is used to assign values to x and y and then the two methods are called.

Java does not support multiple inheritance directly. This means that the class in Java cannot have more than one super class.

Eg:


is illegal/not permitted in Java.

However, to be able to let the java programmers use the immense functionality provided by multiple inheritance, the java language developers incorporated this concept with the use of interfaces. (I will post an article about Interfaces with in few days)

Have you updated your copy of Windows and received the "This copy of Windows is not genuine" notification. Have you ever wondered how to get rid of it?

The Windows Genuine Advantage notification checks if you have a genuine copy of Windows registered to that computer. It allows you to update your computer with the Windows updates. If you have installed it, and you do not have a genuine copy of Windows XP installed, then you may notice an icon at the bottom of your window before you Login. It will make you wait three seconds before allowing you to login.

JUST OPEAN START THEN CLICK RUN.Type "regedit"(without quotes) and press enter.

follow this path:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WPAEvents

u'll find "OOBETimer" in the right side..
double click it..
and in value data
change the last part of first line.....
i dun care just change it.....

save it & close it.....
now opean RUN and type this widout quotes
"C:\WINDOWS\system32\oobe\msoobe.exe /a"

select the option telephone customer service now click next.. now u have a button at the bottom of ur screen "CHANGE PRODUCT KEY" click this... now u see the screen where u have to enter the key...

there u enter one of these:-

(1)T6T38-WJTK6-YVJQ7-YC6CQ-FW386
(2)V2C47-MK7JD-3R89F-D2KXW-VPK3J
(3)JG28K-H9Q7X-BH6W4-3PDCQ-6XBFJ

Open C:\Windows\System32\

Search for WgaTray.exe and Delete it.

C:\Windows\System32\dllcache\ and delete WgaTray.exe here also.

Next you have to modify your registry.

Press the Start Button > Run and type regedit and then press enter.

Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify and delete the WGALOGON folder.

That's all you have to do, now you are WGA free. Just make sure you don't automatically install the WGA update again. Restart your computer to see if you did it correctly. The WGA logo should not appear on your login screen.

DISCLAIMER: We do not condone having pirated copies of Windows on your computer. You should have one CAL per computer. This is for educational purposes only.

JAVAC.EXE
"javac" is the standard compiler in JDK.
"-sourcepath" specifies places where to search for source definitions of new types.
"-classpath" specifies places where to search for class definitions of new types.
Two types of "import" statements behave differently with "javac".
Never distribute your class files with debugging information in them.

>javac 9lesson.java

JAVA.EXE
"java" is the standard application launcher in JDK.
"-sourcepath" specifies places where to search for class definitions of new types.
"-jar" specifies a JAR file and launches the class specified in the manifest file.
"javaw" is identical to "java" except that it will not create the console window.

>java 9lesson

JDB.EXE
"jdb" is a nice debugging tool. But it only offers a command line interface, not so easy to use. It is much more efficient to use graphical interface debugger.
JPDA is well designed, allowing us to debug Java applications remotely.
Debugging multi-thread application is tricky. The following "jdb" notes may help you.
Whenever one thread reaches a break point, all other threads are stopped also.
The command prompt tells what is the current thread.
"where all" tells where the execution are currently in all threads.
"threads" lists all the threads with thread indexes as Hex numbers.

>jdb 9lesson

JAR.EXE
JAR files are ZIP files.
JAR files can have attributes stored in the META-INF/MANIFEST.MF file.
JAR files can be used in Java class paths.
JAR files can be "executable".

>jar xf src.jar

JAVAP.EXE
Used to get back the discription of bitecode:
Eg. If you deleted original source file (9lesson.java). You have only 9lesson.class file

>javap 9lesson

JAVADOC.EXE
Used to create Html file for webpage. 9lesson.java to 9lesson.html

>javadoc 9lesson.java

JVISUALVM.EXE
VisualVM is a visual tool integrating several commandline JDK tools and lightweight profiling capabilities. Designed for both production and development time use, it further enhances the capability of monitoring and performance analysis for the Java SE platform.


JRUNSCRIPT.EXE
Using jrunscript to test regular expressions

JAVA-RMI.EXE
If java-rmi.exe is running on your PC, you should verify that it is authentic. A file name alone is insufficient for identification. Run ProgramChecker Personal Edition and FileAnalyzer to be sure you are running the actual version.

JCONSOLE.EXE
jconsole is a GUI tool that allows you to monitor a local or remote JVM process using the JMX (Java Management Extension) technology.
JVM processes must be launched with the default JMX properties turned on in order to be connected by jconsole.
jconsole displays monitoring diagrams for heap memory usage, counts on loaded classes, counts on threads, and CPU usages.

KEYTOOL.EXE
A key entry in keystore contains a private key and a certificate of the public key.
Certificates can be exported into certificate files out of keystore.
Certificates can be imported from certificate back into keystore.
There seems be to no way to export private keys.
There seems be to no way to generate a certificate of a given public key - signing a public key.

native2ascii.exe
"native2ascii": A command line tool that reads a text file stored in a non-ASCII encoding and converts it to an ASCII text file. All non-ASCII characters will be converted into \udddd sequences, where dddd is the Unicode code value of the non-ASCII character.

"native2ascii" is an important Java tool, because Java compiler and other Java tools can only process files which contain ASCII characters and \udddd Unicode code sequences. If you have any non-ASCII character strings written in a native encoding included in your Java source code, you need to run this "native2ascii" tool to convert your Java source code.

"native2ascii" has the following command syntax:
native2ascii [options] inputfile outputfile

JSTAT.EXE
JDK 1.6 offers 3 nice JVM monitoring tools: jps, jstatd, and jstat.
jps is simple tool that allows you to list all running JVM processes on the local machine or a remote machine.
jstatd is an RMI server that allows you to access local JVM processes by jps and jstat from remote machines.
jstat is a monitoring tool that allows you to obtain sample data periodically from a local or remote JVM process.

APPLETVIEWER.EXE
We talked about how a web browser uses the applet tag to resolve and load an applet from a web server to the browsers JVM. Also, during class we commented that for development purposes, reasons for creating an extra source file. If the Appletviewer is a tool used during development, and if all that it does is scan the HTML file for the applet tag, why not include the applet tag within the Java source file as part of your program documentation.

/*
<APPLET CODE="HelloWorld.class" WIDTH=300 HEIGHT=300>
</APPLET>
*/

>appletviewer HelloWorld.java

Post your information. Please comment

Java is definitely the most popular programming language now, why? Why C,C++ and C# is not popular like Java?

Every Operating system having some executable formats
Eg. Windows - .exe, .cmd, .bat
Eg. Linux - .bin

These files operating system execute directly. Then what about .mp3,.class,.avi...... file. These files Windows can not execute directly its taking media player(Supporters) help.

Winamp software understant the .mp3 file formate. So Windows, Linux Operting System execute this file with the help of Media Players.

Same way after compile the C, C++ programs Compiler creates a executable file (.exe)

Eg : 9lessons.c ----> 9lessons.exe

Windows Operating System Directly access this 9lessons.exe file and print the output. But in Linux(os) can not understand this *.exe format. So C, C++ Dependent Languages

But Java Compiler convert .java file to .class format. Windows execute this file with the help of JRE (Java Runtime Enviroment).

Sun Microsystems Providing Different JREs for Different Operating System


Virus Programmer's Main Aim to interrupt the User's work. So the programmer creates a virus file in Operating System Executable format like .exe, .cmd, .bat (for windows)

If you did a project in C, C++ Language. If any virus attack means it damage the total executable(.exe) files. so C, C++ project files also damage. But java file creates a .class file its like byte code formate. If attact means JRE (Java Runtime Enviroment) only damage. So you java project safe....

What about .Net. It is a best software development package. Why it's not independent ?.

Microsoft People can Write the code for .Net Independent platform. If they will make the next moment onwards no one will buy the Windows Operating System.

Company business aspects they will give Preference to open source operating System like Linux and Solaris.

C, C++ --> Console application programs
Java --> Console - Windows Frames - Web

Links :
Java (JDK) Bin Directory Files Information
Analysis of a Java Class
What Web Server Do?
Google Search Architecture Diagram Overview
The Stock Market Story

Most Popular Articles:-Most Popular Articles Links

If any mistakes please comment me...

The behavior of printf is undefined if there is insufficient no. of arguments for the format string when i am initializing a variable it print variable value, consider this:



ANSWER IS 10.

This was asked by one of my friends. he says," it has to do something with segmentation",so the question is of couse logicaly valid..

The correct answer to the question is undefined behaviour.But if you are wondering why the result prints 10, here's a possible explanation (which seems to work for your platform):

1. Local variables are stored on the stack (int a)

2. The arguments you pass to a function are pushed to the same stack

3. Printf sees a "%d", and assumes that an integer argument is avaliable on
    the stack.

4. It reads an integer from the stack, and picks up the variable 'a', and prints
     it Note that the above explanation seems to work on your (and perhaps many
     other) platform. There is no guarantee that this will be the case with some
     other compiler on some other OS. That's precisely why it is called 'undefined
     behaviour'.

A modifiers assigns characteristics to the methods, data and variables. It specifies the availability of the method to other methods or classes. Variables and methods can be at any of the following access levels:

Default | Public | Private | Protected


public :

No doubt public variable any one can acess, class or methods are universally accessible.

Oxigen public propery...

default :

Classes can be at default level. If you do not give any explicit modifier to a variable, class or method they will be automatically treated as Default.
It means that access is permitted from any method only in classes that are members of the same package as the target.

Eg:


private :

private variables or methods can be accessed only from the methods of the class to which it belongs. A subclass also does not have access to the private variables.

Debit card having security pin number

protected :

a protected variable or method is accessible from any class of the same package or from any subclass is in a different package.

This is like father and child relation.





The first class is SubclassInSamePackage.java which is present in pckage1 package. This java file contains the Base class and a subclass within the enclosing class that belongs to the same class as shown below.


Output

Value of x is : 10
Value of x is : 20
Value of z is : 10
Value of z is : 30
Value of x is : 10
Value of x is : 20

The second class is SubClassInDifferentPackage.java which is present in a different package then the first one. This java class extends First class (SubclassInSamePackage.java).


Output

Value of x is : 10
Value of x is : 30
Value of z is : 10

The third class is ClassInDifferentPackage.java which is present in a different package then the first one.


Output

Value of x is : 10
Value of x is : 30



Please Comment...

The Stanford WebBase project has been collecting topic focused snapshots of Web sites. All the resulting archives are available to the public via fast download streams. For example, we collected pages from 350 sites every day for several weeks after the Katrina hurricane disaster. We also collect pages from government Web sites on a regular basis.

In addition, the project examines how our archives can be explored by historians, sociologists, and public policy professionals.



WebBase was originally funded by the Digital Library Initiatives I and II. During that time the focus of the project was crawling, indexing, clustering and searching technology. The current Google company spun out into the commercial sphere during this phase.



The focus on providing generally accessible, topically coherent archive snapshots was later supported by NSF Infrastructure grant EIA-0322975. An exploratory effort to learn from political scientists about their needs for tools that would allow them to analyze large Web archives was supported by NSF grant IIS-0624725. The project collaborates with the California Digital Library (CDL), and with Stanford's Communications Department.

For a list of available content, please see our access instructions page. A Web page for initiating downloads is also available.