Java Web Start is a software technology that encompasses the portability of applets, the maintainability of Servlets and JavaServer Pages (JSP) technology, and the simplicity of markup languages such as XML and HTML. It is a Java-based application that allows full-featured Java 2 client applications to be launched, deployed, and updated from a standard Web server. Upon launching Java Web Start for the first time, the user may download new client applications from the Web; thereafter these applications may be initiated either through a link on a Web page or (in Windows) from desktop icons or the Start menu. Applications initialize quickly under Java Web Start, are cached on the client machine, and can be launched remotely offline. Additionally, because Java Web Start is built from Java 2 technology, it inherits the Java platform’s complete security architecture.

Since Java Web Start is, in itself, a Java application, the software is platform independent and can be supported on any client system that supports the Java 2 platform. Java Web Start performs an update automatically when a client application is launched, downloading the latest code from the Web while simultaneously loading the application from a previous cache (provided that a cache exists). Java Web Start also provides a Java Application Manager utility, allowing end-users to organize their Java applications as well as providing a variety of options, such as clearing the cache of downloaded applications, specifying the use of multiple JREs, and setting HTTP proxies.

Link: Java Web Start

Practical Uses of PHP

It almost goes without saying that you will want your business website to be compelling, interactive, and secure. All of these characteristics will make your website more effective at bringing in and keeping customers. But how to go about it in a way that is stable, cost-effective, and easy to manage? One popular solution is to use the server-side scripting language PHP to help you solve those problems.

What is PHP?

Created in 1995, PHP originally stood for “Personal Home Page”, however it is now generally understood to mean “PHP: Hypertext Preprocessor”. It was originally designed to create dynamic or more interactive web pages. It is a widely-used, open-source, general-purpose scripting language. PHP is a “high-level” language, meaning that it’s generally more human-friendly (and easier to learn) than other programming languages such as C, ASP or ASP.net.

PHP was originally designed for use in Web site development, but rapidly grew to become a much more robust language. PHP’s primary use is as an “embedded” scripting language, which means that the actual PHP code is embedded in HTML code. When used in this way, PHP enables your web server to process web pages before they’re displayed in the user’s web browser.
Benefits of PHP


PHP is popular because it can be embedded directly into HTML coding.

PHP can be used on all major operating systems and is supported on most web servers.

PHP’s main focus is development for the web, so it has a quick development time and can solve scenarios much quicker than some of the other web design languages.

The latest version of PHP is a very stable and mature language used for web programming much like Java and Microsoft C#.

It is open source so it is free!

Database: It is very easy to write simple scripts which allow your Web site to interact with a database.

Cross-Platform: Both the PHP engine and the PHP code can be used on almost any platform, making it extremely versatile.

Development Tools: You only need a text editor to work on PHP; you do not need any development environment or compilers.

What can you do with PHP?

PHP generally runs on a web server, taking PHP code as its input and creating Web pages as output, however you can also use it for command-line scripting and client-side GUI applications. PHP is an extremely versatile language which enables you to create high-end, stable Web sites with plenty of bells and whistles. Here are just a few of the things you can do with PHP:

Make HTML Web Forms

Store Information in Databases

Remember Web site visitors (cookies and sessions)

Work with Arrays

Work with Files (File Management and downloads)

Parsing and Generating XML (also useful for large quantities of products on e-commerce)

Check which browser your visitor is using

How does PHP Work?

As its name (“PHP: Hypertext Preprocessor”) suggests, PHP derives its power by “preprocessing” hypertext on the server side. This generally means that when the PHP script (saved as a .php file) runs on your web server, it performs the programmed actions, and returns HTML code that will then be sent back to your customer’s web browser. The PHP script itself is not included in the HTML that is sent to the browser, so the PHP code is invisible and secure to the user.

For example, let’s consider the following simple PHP statement. (This example is merely to show the basic syntax of PHP in action. Any detailed discussion of PHP code is beyond the scope of this article.)

In this statement, is the closing tag, and echo is a PHP instruction that tells PHP to output the text that follows it as plain HTML code. The PHP software processes the PHP statement and outputs the following:

Hello World

This is a regular HTML statement that is delivered to the user’s browser. The PHP statement itself is not delivered to the browser, so the user never sees any PHP statements.

Using PHP to Improve Your Website.

PHP has many capabilities features designed specifically for use in Web sites, including the following:

1. Securing Your Website.

PHP can be used to secure your website (or certain areas of your website) so that your customer must enter a valid username and password. This can be used to reward preferred customers and to build an exclusive “membership” component of your business.

2. Working with Web Forms.

PHP can display an HTML form and process the information that the user types in. This can be an excellent way to learn more about your customers by asking them to provide profile information, and to collect information about their specific interests.

3. Communicate with Your Databases.

PHP is particularly adept at interacting with your databases, and storing information from the user or retrieving information that is displayed to the user. PHP handles connecting to the database and communicating with it, so it’s not necessary to know all of the technical details for connecting to or exchanging messages with the database. You tell PHP the name of the database and where it is, and PHP handles the details. All major databases are currently supported by PHP.

4. Customer Loyalty Functions.

You can also use PHP to create a number of different functionalities on your website that will further help you to build customer loyalty, including interactive polls, a guestbook, and a message board.

The popularity of PHP continues to grow rapidly because it has many advantages over other technical solutions. PHP is fast (because it’s embedded in the HTML code, the time to process and load a Web page is relatively short), PHP is free (it is open-source software), and PHP is versatile (is runs on a wide variety of operating systems, including Windows, Mac OS, Linux, and most Unix variants).

Perhaps most importantly, PHP is a very well-established language. There are many user-run Internet communities that make very large amounts of information (and scripts) available. With so much experience behind it, using PHP for certain dynamic features can be a cost-effective and low-hassle way of increasing the stability of your website.

Jeremy Gislason is a leading expert on membership sites, marketing and online business. For more Business Strategies, Membership Site Software and Information visit MemberSpeed.com

Article Source: http://www.free-articles-zone.com

Whether you are just starting your first Java program, or you are a well experienced programmer, your code can not be an error free code and compile successfully from the first time. At the least you may confuse variable names, forget to declare a variable, or miss a semicolon.

Java language errors, just like all other programming languages, can be either syntax errors or logical errors. Syntax errors, also called compile time errors, are illegal use of statements in terms of programming language rules. When the compiler catches them it generates an error message indicating the class name, line number where the error is found, and the type of error. However, sometimes the actual error may not actually be in the line indicated in the message. You would want to look in and somewhere before these lines to locate the error.

This happens because syntax errors can be tricky sometimes; one error may lead to more than one error message. A missing semicolon for example causes the following one or more lines to be invalid, and thus generates error messages for all of them. Once you fix that error, all following messages will be cleared.

When writing a program with Java, syntax errors are almost unavoidable, so do not panic or get disappointed when you encounter them. Some of these errors are very common and you are very likely to encounter one or more of them when compiling your code. The fact is, you cannot avoid them. So the best way to deal with them is to get yourself familiar with them and know how to fix them. Below are some of the most common errors along with their solutions.

Capitalization Errors: Java language is case sensitive, variable names must be exactly the same, Total is not the same as total and not the same as toTal.

The file name is different than the public class name: The class should be saved in a file with exactly the same name; a Shirt class should be saved in a file named Shirt.java. Saving it to a different file name will give a compiling error.

Javac cannot find the class: When you save your classes, or source codes, they have to be in the very same directory where your javac.exe is. This file is responsible for compiling your codes and is created automatically when you download and successfully install the DSK machine. Generally you would install the SDK into your C: drive so there where your javac file will reside. Thus when saving your source code you need to save it in the C: directory in a folder named java.

“javac is not recognized as an internal or external command, operable program or batch file” (for Windows System) or “javac: Command not found” (for UNIX System): This means that your compiler cannot find your javac. This is due to one of two reasons, either you do not have a javac at all because you did not install the correct machine, or you did not set your PATH correctly. In this case you need to properly set your PATH, or you will have to type in the full file name path to execute it.

“Exception in thread “main” java.lang.NoClassFoundError: ‘fileName’: You probably misspelled the fileName, remember that java is case sensitive.

“Line nn: ‘;’ expected”: This means you moved to a new line without signaling to the compiler. When your string, or code line, is too long to fit in one line, you may want to split into two lines. Doing that just by pressing the Enter key will confuse the compiler and generate an error. Instead you will need to concatenate with a ‘+’ sign. That is split your string into two lines, ending the first with a ‘+’ before moving to the second line.

Author Bio
Ashwak Sarhan is a Java tutor for Baker College Online.

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